# KH....Affect plants or not????



## lauraleellbp (Feb 3, 2008)

kH is needed in a planted tank for several reasons. First of all, plants need some trace amounts for use in photosynthesis. Second, kH buffers a tank from extreme pH fluctuations (which will affect livestock before plants but is still relatively important). This buffering effect especially helps in CO2-injected tanks as otherwise the added CO2 could bottom out a tank's pH.

In general, most plants and livestock can adapt to live in varieties of water parameters, as long as those parameters aren't too extreme, and remain stable over time. (Which is one reason buffering is important). IMO I wouldn't try and alter your water's kH.

Different people may have different specific/specialized goals in mind in relation to their kH levels, depending on the water parameters they start with. When you start breeding livestock, this is mostly when specialized needs come into play.

I personally need to increase the kH in my tanks somewhat as my snails have recently started showing a calcium deficiency (white crumbly shells). Shrimp also need some kH in order to moult properly. However, the most delicate/expensive shrimp (CRS, Sulawesi shrimp, etc) have VERY specialized water parameter needs, and some more advanced hobbyists work to change and maintain specific water parameters in order to allow these critters the best chances of breeding and raising babies. Shrimp are just one of the more common examples on this forum... there are many others.


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## mistergreen (Dec 9, 2006)

the problem isn't KH, it's your water softener.
I'm guessing you're using sodium in the softener, and generally, plants don't like too much sodium and they need some GH too.. Calcium and magnesium are nutrients which the softener takes out


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## dewalltheway (Jan 19, 2005)

I use Mortons Salt in the softener. So, if I am using the EI method of dosing, are the plants getting enough of these nutrients back?


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## mistergreen (Dec 9, 2006)

You'd need to add Mg & Ca in addition to the EI dosing.

But the problem is still the sodium. Can you bypass the softener? It'll make things easier.

You can get plants that are sodium tolerant I guess.


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## dewalltheway (Jan 19, 2005)

I believe it will make things worse if I bypass because then I will be dealing with very hard water and high levels of chlorine and other chemicals. Does sodium increase the KH?


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## deicide (Feb 23, 2008)

Some softwater plants will not adapt to water with such a high KH and will melt away so lowering KH will be necessary if you want to grow these types. If you do not want to lower your KH (fight your water as some call it) you should check whatever you are about to buy will grow in high KH water. 

BTW your GH is too low and should be increased as well, aim for a GH of 4~5. 



lauraleellbp said:


> I personally need to increase the kH in my tanks somewhat as my snails have recently started showing a calcium deficiency (white crumbly shells).


So why did you increase you KH if calcium is what you needed, was that a typo or did you use CaCO3?


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## dewalltheway (Jan 19, 2005)

My tank size is 55 gal, using Eco-Complete, DIY CO2 and as I said EI dosing. So...back to the question. Does the level of KH affect plants and if it does what is the best and least costly way of lowering it to reccommended levels.


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## deicide (Feb 23, 2008)

dewalltheway said:


> So...back to the question. Does the level of KH affect plants





deicide wrote said:


> Some softwater plants will not adapt to water with such a high KH and will melt away so lowering KH will be necessary if you want to grow these types.





dewalltheway
said:


> what is the best and least costly way of lowering it to reccommended levels


Get an RO unit, there are a bunch of them selling on Ebay for really cheap, www.buckeyefieldsupply.com or www.airwaterice.com.........


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## lauraleellbp (Feb 3, 2008)

deicide said:


> So why did you increase you KH if calcium is what you needed, was that a typo or did you use CaCO3?


FYI I was going to add some crushed coral but instead added some crushed eggshells (had that handy). Theoretically this will increase the kH if added enough, I'm sure it didn't make a measurable difference b/c I didn't add much. 

Dewalt- My best advice is to leave your kH alone.

Get plants that do well in your tapwater as it is. Everyone's tank is different anyways and so you'll need to experiement with what does well for you along with everyone else.

Anything else will end up being a headache in the long run.


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## Wö£fëñxXx (Dec 2, 2003)

dewalltheway said:


> My tank size is 55 gal, using Eco-Complete, DIY CO2 and as I said EI dosing. So...back to the question. Does the level of KH affect plants and if it does what is the best and least costly way of lowering it to reccommended levels.


To answer your general question, yes it can/will have an affect
depending on plants you are trying to grow.

I wouldn't say that there is a necessary level in general.
If trying to grow Tonina or most any of the other more 
complicated plant sp. then lowering the KH to 4 or less would
be a huge advantage.

I have yet to find a need to add Ca or Mg to RO water,
I do cut it with my semi-soft tap water.

You need an RO unit to lower it effectively.
Do a search on ebay for Aqua Safe Systems for the best buy
to your $$$.

Regards


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## Wö£fëñxXx (Dec 2, 2003)

You can lower the pH only so far with C02.
You will be hard pressed to get it to drop below 6.0

No way you can bottom out the pH on a tank, 
that would be battery acid, impossible to do
under these conditions.

You are confusing that scenario with 02 depletion. 

The lower the KH the easier it is to lower pH and 
02/oxygen.



lauraleellbp said:


> kH buffers a tank from extreme pH fluctuations (which will affect livestock before plants but is still relatively important). This buffering effect especially helps in CO2-injected tanks as otherwise the added CO2 could bottom out a tank's pH.


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## Avalon (Aug 14, 2004)

My thoughts are right in line with Wö£fëñxXx's. I've placed a heavy emphasis on experimenting with KH in the planted aquarium. I've used tap water with a KH of 17dKH, and while I could grow most plants, some were downright difficult to grow...Pogostemon stellata (narrow) comes to mind. It was really difficult to get enough CO2 into the water also.

I ended up buying an RO unit (Aqua Safe Systems on ebay) and using 100% RO water with ADA substrate. There was nothing I couldn't grow and it all grew effortlessly. I used no buffers whatsoever, nor did I add Ca or Mg, only micros and macros.

So does the KH affect plants? Absolutely. Will it keep you from growing plants? No, but it is far easier to grow them in a lower KH water, and it's far easier to dissolve CO2 into the water. I've noticed the following params:

0-5 dKH: You can grow anything.
6-10 dKH: You can grow anything but the ultra soft water plants (Tonina's, Erio's, etc)
10+ dKH: Most other plants, but some will be difficult.

You should either keep your KH low or high. Changing between the two will cause your plants to melt. You can easily keep fish and plants with a KH of 0. You will never cause the pH to "bottom out," but you can suffocate them (the fish) with too much CO2 since it's easier to dissolve CO2 into low KH water.


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## Wö£fëñxXx (Dec 2, 2003)

Avalon said:


> You can easily keep fish and plants with a KH of 0. You will never cause the pH to "bottom out," but you can suffocate them (the fish) with too much CO2 since it's easier to dissolve CO2 into low KH water.


Absolutely, depending on the type of fish one is 
trying to keep it is easier to "choke" some than others.
So, knowing tank type you are trying to achieve whether
soft or not will determine type of fish selected, 
for instance Characins prefer soft to very soft, whereas
Live-Bearers, Loaches etc. prefer it not so soft.

If noting fish gasping or choking at surface, _don't freak out_,
This is what to do, raise the spraybar or lily pipe to break 
the waters surface and turn down C02 just a smidgen.

You add 02 that the fish are looking for at the surface and
releases or offgas the C02 which slowly raises the pH.
Finding that balance is not difficult, but it does take some 
experience with super soft water.

Overall it is not complicated and a much more primitive
procedure than you would usually see on forums.
02 is your friend.


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## Wö£fëñxXx (Dec 2, 2003)

ashappar said:


> I'm in the group of people who see little significance in the whole idea of adding buffers to water. I do add GH, since my RO product water has low TDS around 5-7 and I do see deficiencies if I skimp on calcium and magnesium. My snails have plenty strong shells, I actually wish they were thinner. easier to smash them and feed to goodeidae..


Agreed, if you are keeping snails etc. then a Tonina 
tank is the wrong tank. I keep a TDS of around 10
works good for me.
All my high tech ultra-soft water tanks get 
NPK w/Trace minerals, iron, lots of C02 and small 
amounts of Excel and lots of aeration everyday.
When the lights are not on, the tank is being aerated.
Lots of 02.

I like plants more, so that is what determines my tank.
If I want to keep snail, expensive shrimp, loaches
and live bearers, then they get a different setup
that is not so soft.

I do also agree with mistergreen about the water softner,
that may be OK for around the house,
but not best suited for a planted tank.


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## lauraleellbp (Feb 3, 2008)

I'll back up my statement in that without any kH buffering in a tank you can bottom out pH and end up with biogenic decalcification; rare but still possible.

It's especially possible if you are adding other substances to try and lower pH, such as peat. I had a friend who accidentally ended up with a pH in the 4s that way (his Apistos were happy but not anything else! LOL)


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## mrkookm (Apr 4, 2007)

> I'll back up my statement in that without any kH buffering in a tank you can bottom out pH and end up with biogenic decalcification; rare but still possible.


O boy here we go again, the scary bottoming out of the PH :hihi: Well I've been using *straight RO/DI *water for 1½years with a *KH0*, have never lost a fish, shrimp, experienced the bio whatever and neither has my PH ever bottomed out :hihi: 

If KH is needed for success then I guess I just one lucky guy.

Here is a pic of my DC from beginning to end, there is an 8pm pic but it's not necessary as you can already see I do inject lost of Co2... 

Wana guess what my PH is?


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## Wö£fëñxXx (Dec 2, 2003)

laura,
You are going to make me sit here and write a bunch of words.
I would rather be doing other things.
I use peat in every tank I setup regardless of KH. I question you friends skill
and knowledge with a test kit & soft water.
There are some facts involved with this so called pH crash or "bottom out"
which is actually attribute to C02 poisoning or oxygen depletion or just plain
stupidity.










Biochemical Oxygen Demand, or BOD, is a measure of the quantity of oxygen consumed by
microorganisms during the decomposition of organic matter. BOD is the most commonly used
parameter for determining the oxygen demand on the receiving water of a municipal or industrial
discharge. BOD can also be used to evaluate the efficiency of treatment processes, and is an
indirect measure of biodegradable organic compounds in water.
Imagine a leaf falling into a stream. The leaf, which is composed of organic matter, is readily
degraded by a variety of microorganisms inhabiting the stream. Aerobic (oxygen requiring)
bacteria and fungi use oxygen as they break down the components of the leaf into simpler, more
stable end products such as carbon dioxide, water, phosphate and nitrate. As oxygen is
consumed by the organisms, the level of dissolved oxygen in the stream begins to decrease
Water can hold only a limited supply of dissolved oxygen and it comes from only two sourcesdiffusion
from the atmosphere at the air/water interface, and as a byproduct of photosynthesis.
Photosynthetic organisms, such as plants and algae, produce oxygen when there is a sufficient
light source. During times of insufficient light, these same organisms consume oxygen. These
organisms are responsible for the diurnal (daily) cycle of dissolved oxygen levels in lakes and
streams.
If elevated levels of BOD lower the concentration of dissolved oxygen in a water body, there is a
potential for profound effects on the water body itself, and the resident aquatic life. When the
dissolved oxygen concentration falls below 5 milligrams per liter (mg/l), species intolerant of low
oxygen levels become stressed. The lower the oxygen concentration, the greater the stress.
Eventually, species sensitive to low dissolved oxygen levels are replaced by species that are
more tolerant of adverse conditions, significantly reducing the diversity of aquatic life in a given
body of water. If dissolved oxygen levels fall below 2 mg/l for more than even a few hours, fish
kills can result. At levels below 1 mg/l, anaerobic bacteria (which live in habitats devoid of
oxygen) replace the aerobic bacteria. As the anaerobic bacteria break down organic matter, foulsmelling
hydrogen sulfide can be produced.
BOD is typically divided into two parts- carbonaceous oxygen demand and nitrogenous oxygen
demand. Carbonaceous biochemical oxygen demand (CBOD) is the result of the breakdown of
organic molecules such a cellulose and sugars into carbon dioxide and water. Nitrogenous
oxygen demand is the result of the breakdown of proteins. Proteins contain sugars linked to
nitrogen. After the nitrogen is "broken off" a sugar molecule, it is usually in the form of ammonia,
which is readily converted to nitrate in the environment. The conversion of ammonia to nitrate
requires more than four times the amount of oxygen as the conversion of an equal amount of
sugar to carbon dioxide and water.
When nutrients such as nitrate and phosphate are released into the water, growth of aquatic
plants is stimulated. Eventually, the increase in plant growth leads to an increase in plant decay
and a greater "swing" in the diurnal dissolved oxygen level. The result is an increase in microbial
populations, higher levels of BOD, and increased oxygen demand from the photosynthetic
organisms during the dark hours. This results in a reduction in dissolved oxygen concentrations,
especially during the early morning hours just before dawn.
In addition to natural sources of BOD, such as leaf fall from vegetation near the water's edge,
aquatic plants, and drainage from organically rich areas like swamps and bogs, there are also
anthropogenic (human) sources of organic matter. If these sources have identifiable points of
discharge, they are called point sources. The major point sources, which may contribute high
levels of BOD, include wastewater treatment facilities, pulp and paper mills, and meat and food
processing plants.
Organic matter also comes from sources that are not easily identifiable, known as nonpoint
sources. Typical nonpoint sources include agricultural runoff, urban runoff, and livestock
operations. Both point and nonpoint sources can contribute significantly to the oxygen demand in
a lake or stream if not properly regulated and controlled.
Performing the test for BOD requires significant time and commitment for preparation and
analysis. The entire process requires five days, with data collection and evaluation occurring on
the last day. Samples are initially seeded with microorganisms and saturated with oxygen (Some
samples, such as those from sanitary wastewater treatment plants, contain natural populations of
microorganisms and do not need to be seeded.). The sample is placed in an environment suitable
for bacterial growth (an incubator at 20o Celsius with no light source to eliminate the possibility of
photosynthesis). Conditions are designed so that oxygen will be consumed by the
microorganisms. Quality controls, standards and dilutions are also run to test for accuracy and
precision. The difference in initial DO readings (prior to incubation) and final DO readings (after 5
days of incubation) is used to determine the initial BOD concentration of the sample. 

Ultimately it is the lack of oxygen that kills fauna in a plant tank, very high levels of C02 can do 
this also obvioulsy, but with high levels of C02 you also get lower levels of oxygen, so the proper 
amount of surface agitation is vital.
High quality filter and media plays a vital role in this environment also because it helps control nitrate,
nitrite and ammonia..nitrate is also an acid-nitric acid.

BIOLOGICAL FILTERATION

It is no exaggeration to say that the condition of an aquarium depends much on the performance and flow
of the biological filtration.
When the filter's micro-organisms are thriving, the water will be crystal clear and there is no algae growth.
The chemical reaction that expresses the oxidation process carried out by 
the nitrobacteria which converts harmful ammonia into harmless nitrate is NH3; NO2; NO3. The bacteria 
that converts ammonia (NH3) into nitrite (NO2) is called Nitrosomonas, andthe bacteria that converts
that into nitrate (NO3) is called Nitrobactor. 
Studies shown that the remaining nitrate is about 70times less toxic than nitrite, but if enough accumulates
in the water it can still be harmful. Therefore, 
it is always necessary to frequently change the aquarium water even when using a top-of-the-line filter.


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## lauraleellbp (Feb 3, 2008)

I really do appreciate the time you spent on that post! (If you'd rather be doing other things then by all means do them... LOL I don't think you're being mean at all- I love learning so appreciate a good discussion)

However, I think we're talking a little apples and oranges. I was speaking specifically 1) how lack of kH can = unbuffered pH swings, and 2) of biogenic decalcification. Not arguing any issues of dead organic matter decomposition and the impact on O2 levels at all? Absolutely excessive decaying organic matter in a tank will affect O2 levels and the nitrogen cycle- but I was referring to photosynthetic processes, not decomposition.

"During the nitrification process a small amount of KH is "consumed", additionally some plants and most algae will strip bicarbonate in water with a really low amount of CO2. When this happens in poorly buffered water or rather water with a low KH, you could see major swings in pH as the KH is reduced...first very low, then very high if in a bright light situation. But again, for most scenarios where either the tank water is sufficiently buffered (KH above 3) or the hobbyist is doing routine weekly water changes the chances are very slim that any KH loss would be problematic. It should also be noted that whether plants remove CO2 faster than it can diffuse is completely dependent on overall plant mass, plant species, amount of lighting, and food available to the plants...In a typical situation you know that as CO2 levels increase the pH lowers and conversely when CO2 levels are reduced pH levels rise.

Under very bright light situations it is possible that all CO2 could be removed from the water...this sets into motion a process called biogenic decalcification where the pH skyrockets to 9.0 or higher, during this process calcium will form hard marl deposits on plant leaves and other surfaces in our aquariums...actually this situation is only likely to occur where there is sufficient carbonates in the water...in situations where KH drops to zero the pH would continue to plummet. Only is situations where there is sufficient KH but lacking CO2 can the pH skyrocket and biogenic decalcification occur. 

To back up a bit...in my previous post I listed items that impact whether CO2 can diffuse faster than plants can remove it from the water. I failed to mention another issue that is also critical...water movement. In aquaria that isn't getting forced CO2 injection it is very important to make sure that there is plenty of water movement. CO2 goes into and out of solution (in non injected tanks) best at the water surface in contact with air. Exposing as much water to the air will help maintain CO2 gas equilibrium with the atmosphere. This is one situation where increasing surface agitation or water movement can actually increase CO2 levels. This is of course counterproductive when we are injecting CO2 to levels above equilibrium.

The best way to understand BD is to work with the CO2 formula.

CO2 (PPM)= 3 * KH * 10^(7-pH) (you can also use several online CO2 calculators instead)

Using this you can plug in numbers and see how the closer the CO2 ppm comes to zero the higher the pH becomes. Once plants remove most to all dissolve CO2 and begin to remove calcium bicarbonate from solution you will see calcium carbonate precipitate (visibly) and the pH will skyrocket to the high 8's or 9's. Again the key is bright lighting. Frankly, in normal aquaria we should never see a full blown case of BD." 

- from Steve Hampton

Adding peat (humic acid) to an unbuffered water column will lower pH - this from is Peter Hiscock's book (my guess mkoom is that even with a 0 kH reading your tank is sufficiently buffered by other means/TDS and/or you aren't adding acids to your tank):


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## mrkookm (Apr 4, 2007)

> Adding peat (humic acid) to an unbuffered water column will lower pH - this from is Peter Hiscock's book (my guess mkoom is that even with a 0 kH reading your tank is sufficiently buffered by other means/TDS and/or you aren't adding acids to your tank):



Well mrkookm's book *proves* carbonates is not needed becasue he *currently uses* *no KH * due to using straight RO/*DI* (not RO only) water and he can keep *healthy* live stock like anyone else as long as a little common sense is applied here and there.

I not an aquascapist so I don't use any fancy stones, driftwood, crab shells, egg shells or anything for that matter that will buffer my water  I'm a collector of rare/difficult to maintain plants so whatever makes them healthy is my ****utmost priority*** *and KH isn't one of them. 

I'm not telling anyone not to use a KH0, just stating that it's not needed and I don't have to read it in the book and wonder if  ....*like I said I currently use no KH * :thumbsup: 

Here is my TDS before my water change after adding in CA/MG 7 days ago and ferts for 1 week.


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## mrkookm (Apr 4, 2007)

dewalltheway,

Like others have suggested make your plant selection on what will grow in you're specifc KH range. Unfortunately most of the nicer sp out there are softwater and while few will possibly adapt some will not.

With this info you can now make your decision which direction you want to based on the selection of plants you will want to maintain.....good luck!


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## Wö£fëñxXx (Dec 2, 2003)

Again, you can lower pH only so far in aquaria with the use of C02
at the rates that we use it with or without KH buffering.
You can not make the pH bottom out that is absolutely false.
To bottom out pH=turning tank water into battery acid.
I think your arguments are false and very extreme claiming 
wild pH swings or "bottoming out" pH and biogenic decalcification. 



> However, I think we're talking a little apples and oranges. I was speaking specifically 1) how lack of kH can = unbuffered pH swings, and 2) of biogenic decalcification. Not arguing any issues of dead organic matter decomposition and the impact on O2 levels at all? Absolutely excessive decaying organic matter in a tank will affect O2 levels and the nitrogen cycle- but I was referring to photosynthetic processes, not decomposition.


Decomposition does play an important part in planted aquaria which helps in
the overall stability of the enclosed eco-system, thats why I 
post the BOD info.
What does the photosynthetic processes have to do with buffering KH
and pH fluctuations?
If you are injecting C02, there will be no need of worry about it 
being "stripped", adding CO2 is done not to maintain pH or to keep plants from
chewing through KH, it's added to increase and stimulate plant growth.
This confuses the variable of interest, in this case KH and it's effect on plants.
If you have poor CO2 or poor NO3, will it matter if the KH is 1 or 10? no.
Using aeration instead of a buffer is healthier for the plants and fish
neither one of those need sodium bicarb.

You are free to add as much buffer as you want though, I'm not saying that you can't.

However, I will boldly dispute you telling other members that it is very much a need
or they will have disasters because that is pure BS.

My years of experience with RO/DI and no buffer I wrote my own book,
which blows these other theory's you mention out of the tank.

Get you an empty tank fill it with RO and see if you can make the pH
bottom out then come back and state your claim and we can analyze
your process.


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## lauraleellbp (Feb 3, 2008)

Again I think we're arguing semantics. To me a pH in the 4s IS "bottomed out" b/c most fish would not be able to handle that type of swing. "Could" and "will" are two very different words...

The point I was making is that when a person goes about artificially altering their water parameters (especially when using peat or some of the other commercial products on the market) they DO run the risk of pH dropping to levels that will kill their livestock and probably also have a negative impact on their plants. 

I did do that to one of my tanks back in my early inexperienced years in the hobby, I'm sure you've run across others who've done it as well, I see no reason to repeat the exercise? RO isn't the culprit- using those products in an unbuffered tank is the issue (the products are pretty much worthless is really the point I'm making here).

The use of RO/DI water doesn't have any bearing one way or the other if you aren't adding any of these products. I've never advocated not to use RO/DI (IMO it's the only safe way to lower TDS), I'm not at all arguing with your experience, mrkoom- you aren't the one talking about finding a way to alter your parameters and obviously have the experience to grow plants suitable to your water and change them if needed LOL 

Biogenic decalcification IS an unlikely extreme, and I pointed that out when I first brought it up. It can happen, however. High light, CO2-injected tanks with substrates like AS that strip TDS from the water column would by definition be more at risk should the CO2 suddenly fail. 

Cracks me up how people love to bash books- good books are written by people BASED on their experiences. Books remain a great form of communicating experience, typically more reliable to what's on the internet b/c they are peer-reviewed before publication.

kH is needed in minute quantities during photosynthesis, kH serves as a buffer or safety net against pH swings- that was the whole point of my OP.

Do I think it's *that* big a deal? Of course not- Dewalt wanted discussion and IMO that's what we've given him


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## tacks (Jun 19, 2006)

I just wanted to say thank you for ths great read. There certainly are some very knowledgeable people here. thanks Ed


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## lauraleellbp (Feb 3, 2008)

ROFL @ 'biogenically decalcified asteroid' Nice one


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## dewalltheway (Jan 19, 2005)

Well..I appreciate everyones comments and help with this situation and I believe I am going to go with experience on this issue. I purchased some plants from Wö£fëñxXx (rotala Vietnam, & stellata). They were beautiful when I got them and now just after a little over 1 week they are suffering (will post pics later). I just purchased a RO/DI unit from Dr Foster's & Smith and should be here Wed. or Thurs. (4/30 or 5/1/08) I will start using this water and see how the plants are affected and this will determine if KH affects plants. I will post pics of this experiment as well as water parameters. If there is anything else that you would want me to document, please let me know.

I also agree with tacks about the knowledge of people on this forum. That is why I come here to ask these questions. Thanks to everyone! :thumbsup:


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## dewalltheway (Jan 19, 2005)

lauraleellbp said:


> Again I think we're arguing semantics. To me a pH in the 4s IS "bottomed out" b/c most fish would not be able to handle that type of swing. "Could" and "will" are two very different words...
> 
> The point I was making is that when a person goes about artificially altering their water parameters (especially when using peat or some of the other commercial products on the market) they DO run the risk of pH dropping to levels that will kill their livestock and probably also have a negative impact on their plants.
> 
> ...


Laura...discussion is exactly what I wanted so that these types of issues that aquarist deal with day in and day out can be given a clear perspective on these types of issues and I appreciate your comments as well as everyone else. If society all thought alike, life would be pretty boring. Diversity and discussion is what spurs on change and growth and helps society to move forward.


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