# CO2 and Algaes



## DarkCobra (Jun 22, 2004)

32Bit_Fish said:


> I don't have 4DKH solution, so no drop checker in the tank for me to see CO2 level. I heard drop checker isn't accurate measuring CO2 level anyway. So I didn't bother to buy 4DKH solution. So I'm relying on other means to estimate CO2 level in the water.


A properly set up and maintained drop checker with 4dKH solution is actually the _best_ method of determining how much CO2 you have in your tank, short of electronic sensors costing much more. Those who claim a drop checker is inaccurate are doing a grave disservice to the hobby. Read their claims carefully - notice how they never say _why_ they think it's inaccurate, or _how_ inaccurate it is? It's left entirely to your imagination, assuming that you'll think the worst and therefore avoid drop checkers. Without any meaningful measurements _of your own_ to go on, you'll have no choice but to follow their method blindly and without question. The same folks will tell you to avoid test kits, and so on, same deal.



32Bit_Fish said:


> The norm of CO2 DPS for a tank that is larger than 55G is 3 DPS?


BPS (bubbles per second) is actually the _worst_ method. It sort of tells you how much CO2 is going in, but not how much is successfully being diffused. How much is being used by plants, or escaping due to surface agitation. What the _real tank level_ is. And bubble _size_ can differ from counter to counter too. So for all these reasons, a BPS that works for another person, probably won't work in your tank, even if tank size is the same.



32Bit_Fish said:


> The old algaes on plants are still there. How long does CO2 take effect on algaes?


CO2 does not kill algae. It feeds algae, just the same as the plants. But get the plants growing well enough and they will typically win out over algae, though exactly how they do this is mostly unknown.

A drop checker with 4dKH solution turns green at 30ppm. This is more than enough in most tanks for the plants to win out over algae.

But some tanks may need more. This does _not_ mean the drop checker is inaccurate. It's job is simply to report CO2 level. If it's green, then there really is close to 30ppm in such a tank. It's not the drop checker's job to tell you if 30ppm is _enough for that particular tank_.

So if 30ppm isn't enough, you increase CO2 further, and see what happens. Perhaps at some point the algae finally stops growing or goes away. But it took a lot more than 30ppm to accomplish that, _then you almost certainly have another problem_. Which should be looked into and solved, rather than needlessly using so much CO2 and stressing fish. And without a drop checker, how will you know if that is the case?


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## 32Bit_Fish (Jul 8, 2012)

Thanks for your response. I've seen people stated the dropper checker isn't accurate even with the best/accurately made 4dkh solution.

But anyway, where should I start? Buying 4dkh solution from the Internet? Or buying a gram scale to make it my own?


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## DarkCobra (Jun 22, 2004)

32Bit_Fish said:


> Thanks for your response. I've seen people stated the dropper checker isn't accurate even with the best/accurately made 4dkh solution.


The accuracy mainly depends on our ability to distinguish between shades of color. We say if it's green, then CO2 is 30ppm. It could really be 25ppm, or 35ppm.

That's still better than having no idea of the level at all, or using an even less accurate method. The real question is, is it accurate _enough_? Anything can be called inaccurate. A scientist in a lab may call anything less than 99.9% perfect inaccurate. But we're hobbyists!

Imagine that because your tank is really at 25ppm instead of the intended 30ppm, you get algae. Then your tank actually needs _more_ than 30ppm to have a margin of safety and increase stability, so you could shoot for the 40ppm neighborhood and a yellow-green drop checker.

But why was that tank so _sensitive_ in the first place, that 25ppm vs. 30ppm would make such a difference?

It could be you're _intentionally_ running at quite high light, in which case your tank legitimately needs more CO2 to keep the plants adequately fed, and you accept this as well as all the other high-maintenance aspects of such a tank.

Or if could be that you're _accidentally_ running more light than you think. Or maybe you have insufficient plant mass, etc. In which case you have a problem that can and should be solved, instead of covering it up by just piling on the CO2; and if you do solve this problem, your tank will be more stable and lower maintenance than you could ever make it with CO2 alone. Then, if you slip up on what maintenance is necessary (we all do occasionally), the tank doesn't rapidly turn into a disaster zone. This is a very good thing!



32Bit_Fish said:


> But anyway, where should I start? Buying 4dkh solution from the Internet? Or buying a gram scale to make it my own?


I'd say get it from the Internet, at least at first. My first small batch of 4dKH was homemade, but I had doubts about how accurate it was, so I ended up buying a bottle anyway to compare against. Turns out my DIY 4dGH was fine, but the ready-made stuff was so cheap and convenient, and lasts long enough, that I never made DIY 4dKH again.


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## 32Bit_Fish (Jul 8, 2012)

I can tell I get more and more algaes now than before I started using CO2. Why? Let me try to figure out the cause here... 

- Not enough plants in the tank? There are a lot of plants in the tank. It looks like a jungle. It's a dirt tank with root tabs added in the substrate. Amazon sword has grown from a little 6" to 12" within a few weeks.

- Too much light? I only have Catalina T5 HO, 2x39w (36" fixture) on a 75G. I wouldn't consider this is high light even though I leave it on 10 hrs a day

- Surface agitation - I am only running a canister filter, however spread bar is facing upward to the water surface, but it doesn't create water splash like a HOB does. 

Would you recommend any commercial 4DKH solution? I found 4 DKH referrence solution 4 oz bottle. Have you had any experience with this product?


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## DarkCobra (Jun 22, 2004)

Let's start with this:



32Bit_Fish said:


> Too much light? I only have Catalina T5 HO, 2x39w (36" fixture) on a 75G. I wouldn't consider this is high light even though I leave it on 10 hrs a day


I run my DIY 2x39W T5HO, with efficient reflectors, close to the top of my 46G bowfront. I have high light. Tank dimensions are 36"L x 15"W x 20"H.

You have the same wattage and lighting type, and looking at some Catalinas it appears they too have efficient reflectors. A standard 75G is 48"L x 18"W x 21"H. Compared to mine, yours is larger in length (L), and front-to-back (W), but only 1" deeper (H).

So if your light is also close to the top of your tank, you likely have high light too. At least in the middle of your tank, not the ends - since your tank is wider than the bulbs.

And if you do have high light, in _any_ part of your tank, then you have to run it accordingly. Plenty of CO2, water column fertilization (you've only mentioned root tabs so far), and keeping algae at bay is corresponding harder. Small differences in photoperiod can be critical, I run 9 hours/daily which works fine, 10 hours proved troublesome. High light is also more than swords need to be spectacular, though I don't know what other plants you may have.

Lighting is not my specialty, but if you measure the actual distance from bulbs to substrate, I can provide a better estimate for you.



32Bit_Fish said:


> Surface agitation - I am only running a canister filter, however spread bar is facing upward to the water surface, but it doesn't create water splash like a HOB does.


Impossible to determine anything about actual CO2 levels from this, or any other information so far provided. It must be measured, no way around it. Even a less accurate method, like looking up CO2 level from a pH/KH chart, is better than nothing.



32Bit_Fish said:


> Would you recommend any commercial 4DKH solution? I found 4 DKH referrence solution 4 oz bottle. Have you had any experience with this product?


Direct Ebay links are disallowed, but if it's the one listed exactly as "4 dKH Reference Solution For Co2 Drop Checker pH" on Ebay, that is the one I use. Green Leaf Aquariums also sells one a lot of folks use. I've never heard anyone say they bought a bad 4dKH, so really, anything should be good. The major pitfall is cheap import drop checkers which contain only indicator drops designed to be used with tank water instead of 4dKH, and that produces terrible results. Throw away those drops, use drops from a standard pH test kit instead, and with 4dKH.


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## rottincorps (Oct 14, 2013)

I get my 4dkh from green leaf aquariums, it's pretty cheap and last a long time. I also have a 75 gallon heavily planted tank. My BPS are going way faster then you can even count to get to 30 ppm. A drop checker is only gonna get you in the ball park. Ones your close you need to start paying attention to your plants and fish for how they are reacting.as far as my experience goes with algae, I don't think adding co2 is going to get rid of your existing algae but it will help keeping new algae from forming by speeding up your plant growth,which should help with consuming nutrients. I think you would be better off trimming off the plants with algae a little at a time. Then tuning in your co2 with a drop checker or by monitoring you ph. I am still relatively new to this but that is my experience so far .


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## 32Bit_Fish (Jul 8, 2012)

My PH did drop from 6.8 to 6.4 within a week after using CO2. So that means the tank water is absorbing the CO2, correct? I'm getting the solution for the drop checker. How often do I need to replace the 4dkh? It's a 4oz bottle. How long does it last?

19" between substrate and light.


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## rottincorps (Oct 14, 2013)

I usually replace the. 4dkh in my drop checker every 2weeks. The way I understand it as far as ph, to get to around 30ppm of co2 you should see your ph drop of a whole point.so if you started at. 6.8 you would want it down to 5.8.it sounds like your getting the co2 in there just not enough.i would think 4oz bottle would last you a few months at least if you don't waste any filling your drop checker.maybe someone else can comment on the ph drop but that's how I understand it.


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## DarkCobra (Jun 22, 2004)

I agree with [rottincorps], with two caveats:

1) The mix in the drop checker can last much longer than two weeks, as long as it's not contaminated by tank water. Excluding special cases (like the drop checker suction cup falls off), this usually happens because bubbles enter the the drop checker opening then pop, ejecting fine droplets of water which can get further inside. My tanks have few bubbles and I place the drop checker away from any particular bubble sources. So I get many months of use before I have to change the solution, and a 4 oz. bottle of 4dKH has lasted me a couple of years.

2) The pH drop of one point is a good rule of thumb, but it does break down in some cases. If tank KH is low, one point of pH drop results in less than 30ppm - maybe much less if KH is really low. It can also fail if there are significant amounts of non-carbonate buffers, though I suspect this is probably fairly rare.



32Bit_Fish said:


> 19" between substrate and light.


My distance is 20" (because my DIY fixture, although it's directly on top of the tank, is not as sleek as a commercial one). Estimating your light level using two different methods:

http://www.plantedtank.net/forums/showthread.php?t=105774
http://www.plantedtank.net/forums/showthread.php?t=184368

You have either high light. Or _very_ high light, where the amount of light energy actually exceeds what plants can use, and only algae benefits from the excess.

From what you've told me, you were hoping for medium light.

Try raising the fixture 5" if possible. If not, let me know and we'll explore some other options. Also, reduce photoperiod to 8 hours, it can be increased again later once light levels and algae are under control. Note that these are somewhat conservative suggestions, algae is easier to prevent than get rid of once established, and further temporary reductions of light level/photoperiod may be necessary. But we don't have to jump to extremes right off the bat, we can observe effects and take further steps as necessary.


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## 32Bit_Fish (Jul 8, 2012)

Ok, I've reset the timer to have 8 hours of photoperiod. Let's see if that would help controlling the algaes.

I use the following liquid fertilizers once a week. 
-SeaChem Flourish
-SeaChem Potassium
-SeaChem Iron

The liquid fertz listed above are almost two yeas old. All of them were opened since purchase. Flourish bottle has been in the fridge while other bottles have been kept in room temp. Just to confirm with you guys, they do not have an expiry date. No shelf life for me to worry about? I found this info on other forum. But like to double check with you guys. 

I've never had good results of using liquid fertz. So I haven't been diligently using them on the tank. I figure I am already using root tabs, CO2 and good light. That should be good enough helping the plants to grow. I have a lot of fish in the tank, so fish food and waste make the water very nutrient. 

The light fixture is on legs, so I would not be able to raise its height. 

I get fuzzy algae on plant leafs. However, my angel fish is eating them very often, hopefully not ripping the leafs off in the process. 

I've just increased DPS to a countless number. Hopefully it would help resolving the algae outbreak issue.

Algae

Algae pic #2

Algae pic #3


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## DarkCobra (Jun 22, 2004)

No shelf life on the liquid ferts. I've heard they can get cloudy, but doesn't seem to affect their efficacy. Give them a quick shake before use.

A reduction in photoperiod and increase in CO2 may not be enough alone to turn this around. We can try it and see, but give some thought to how you might decrease light intensity, should you find it necessary. Finding a way to hang the lights over the tank would be best, especially since the bulbs are shorter than the tank, as it would improve how uniformly the tank is lit.


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## 32Bit_Fish (Jul 8, 2012)

DarkCobra said:


> No shelf life on the liquid ferts. I've heard they can get cloudy, but doesn't seem to affect their efficacy. Give them a quick shake before use.
> 
> A reduction in photoperiod and increase in CO2 may not be enough alone to turn this around. We can try it and see, but give some thought to how you might decrease light intensity, should you find it necessary. Finding a way to hang the lights over the tank would be best, especially since the bulbs are shorter than the tank, as it would improve how uniformly the tank is lit.


I can simply turn one bulb off and just leaving one 39w T5 on for 8 hours a day. I've never thought I have hight light on my tank because the red plants I bought lose the brightness of the red color within 3 days in my tank. I have seen the same plant showing beautiful reds in other people's tank and that guy told me he got 4x54w T5HO on them. So I've always thought I need to put more lights on my tank. 

What role of fertilizer in this case? People said I need to dose fertilizer in the tank when there is high light and high CO2 level. I may consider buy dry fertz if there is a need. 

Let's see how would this turn out with 8 hrs of 78w T5HO and increased CO2 injection. I tested the PH level yesterday after I increased CO2 amount. I get 6.2 dropped from 6.8. So I may still need to increase more CO2. 

The fuzzy algaes are taking over my tank. Some plants in the back are completely covered by the algae, I couldn't even see the stems or leafs.
It's frustrating.


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## DarkCobra (Jun 22, 2004)

32Bit_Fish said:


> I can simply turn one bulb off and just leaving one 39w T5 on for 8 hours a day.


Ok, good. Not sure how uniformly lit that would leave the tank, but it's an emergency option at least.



32Bit_Fish said:


> I've never thought I have hight light on my tank because the red plants I bought lose the brightness of the red color within 3 days in my tank. I have seen the same plant showing beautiful reds in other people's tank and that guy told me he got 4x54w T5HO on them.


There's a number of tricky reasons that can happen.

1) Plants bought from the more commercial farms may be grown emersed, out of the water, and blasted with huge amounts of light. Since they're not in water, no worries about algae. But when you put them in water, they'll often undergo a lengthy adaptation process, including paling out.

2) Trimmings from any source are often short. Light spreads out and gets weaker from the top to bottom of a tank. The plant will suddenly start getting red once it reaches the right height.

3) And many red plants are redder on the underside of the leaf. If you're viewing them from the top, you're not getting the full effect (especially if conditions aren't right and they're accumulating GSA on the top). Again, looks better when they get taller.

Here's an older pic I have handy of my 46G, which I think clearly shows #2 and #3 at work for Alternanthera reineckii and Limnophila aromatica:










Shortly after this pic, I replaced my old bulbs, which resulted in the "red line" going further down the tank. (And corrected a calcium deficiency that was stunting Alternanthera, which helped too.)

As for 4x54W T5HO, even more trickiness applies. First, take a look at my hood:










Notice how the reflectors are wide, and actually wrap around the side of the bulbs? These are efficient reflectors. They catch all the light that isn't going down, and redirect it that way, at an angle where the light doesn't spread out too much between top and bottom. A lot of commercial four-bulb fixtures look like this:










The reflectors are poor, only covering the backside of the bulbs. The bulbs are so tightly packed that what light is reflected by the reflectors may not make it out anyway. There's large light spread between the top and bottom of the tank. If these were 39W bulbs, it wouldn't produce twice the light of mine or yours. I doubt it could even match my two-bulb fixture at the substrate!

Now where you find a _good_ four-bulb fixture, you'll find the owner usually has a deep tank. Or suspends the light some distance over the tank to reduce intensity. Or keeps the plants trimmed very low and away from excessive light at the top of the tank, if you've seen pictures of [Plantbrain]'s tanks you'll see he does this a lot. Or some combination of all three.

So now I think you'll see why comparing against pictures and lighting for other people's tanks is tricky. Lots of variables that aren't easily described. And I haven't even gotten into things like overzealous color enhancement, either manually or applied automatically by the camera...



32Bit_Fish said:


> What role of fertilizer in this case? People said I need to dose fertilizer in the tank when there is high light and high CO2 level. I may consider buy dry fertz if there is a need.


With lower light levels, plants can deal with lower nutrient levels. It may be hard for them to slowly collect what they need, but they have the luxury of time.

With high light and CO2, plants are growing fast, they need lots of nutrients and they need them _right away_. Even a nutrient is technically available, if it's in low amounts, it may not be able to collect it fast enough to prevent deficiency. And any deficiency will wreck a plant in a hurry.

Remember I mentioned a calcium deficiency for my Alternanthera? My first clue was that it was growing fine when shaded, but stunting under full light. There was calcium available, just not enough to support fast growth for this particular plant. Easy fix, I doubled the calcium added after each water change.

That's why for high light tanks, folks usually dump large excesses in the water, then remove most of what goes unused with a large weekly water changes. It's the easiest and most reliable way to prevent a deficiency under these conditions.

It _can_ also be done with substrate fertilization (like root tabs), and light (or no) water column ferts. It's just trickier. With water column ferts, you're fairly sure everything required is there, as you're adding it regularly. With substrate ferts, you never know when something is going to start running low. Even if the root tabs aren't depleted, they're usually time-release in nature; so if you haven't added enough tabs, plants may be sucking up nutrients faster than they're released.

Plus a common method of trimming stem plants is cutting off the nicer top portion, replanting it, and throwing away the bottom. Which means the plant, lacking roots, is temporarily unable to properly access the major source of nutrients. And in a high light tank, stem plants require more frequent trimming!


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## 32Bit_Fish (Jul 8, 2012)

It's interesting that you are calling my tank has high light or very high light. Someone else on the board just told me I have a low light tank given the fact that 2x39w T5HO on a 75G.

I guess I have to read and study the article you provided in your reply.

I want to see how the algae issue going to turn out with 8 hrs of two bulbs on. I may need to turn one bulb off later.

Someone said my current algae issue is the product of new tank syndrom. He could be right. The tank is two month old even though partial substrate and filter medias were transferred from a 1.5 yrs old tank. 

I guess I need to sit back and relax. The algae issue may get improved as the tank ages.


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## DarkCobra (Jun 22, 2004)

32Bit_Fish said:


> It's interesting that you are calling my tank has high light or very high light. Someone else on the board just told me I have a low light tank given the fact that 2x39w T5HO on a 75G.


I saw that. I'd bet a steak dinner he used the hopelessly outdated "watts per gallon" rule, which only worked for old inefficient T8 fixtures, and rather poorly at that. By that rule, you have 1WPG, which is low light. And so do I. Wow, look at the reds I'm getting with "low light"! :biggrin:



32Bit_Fish said:


> Someone said my current algae issue is the product of new tank syndrom. He could be right. The tank is two month old even though partial substrate and filter medias were transferred from a 1.5 yrs old tank.


I think that "new tank syndrome" is probably explainable by other things. I start new tanks primarily with plants taken from my other tanks, that are already adapted to my tapwater and other conditions, rather than those which may take a few weeks to adapt. Pack them with enough plants from the start, rather than letting them gradually grow in. And I mostly get light/CO2/nutrients right on the first try. As a result I don't see "new tank syndrome" anymore, unless I've made an error. Or use new pea gravel from a home improvement store, the silicate dust from that is usually good for couple of weeks of diatoms, and a very fat and happy otocinclus.

Doesn't hurt to wait and see, just make sure you're not losing ground in the process. If algae is getting out of control fast and plant health is decreasing, you'll need to step up and try something else.


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## 32Bit_Fish (Jul 8, 2012)

It was very obvious that the aglaes were started taking over my tank soon after I turned on the 2nd bulb. It was a couple days ahead of the CO2 up and running. Sometime I wonder whether the CO2 created algaes.

I had very algaes when there was one bulb(39w) on for 10 hours and without the CO2. The extra lighting definitely made things worse and running CO2 did not help prevent algae issue and probably fluctation of CO2 level made thing worse. 

What ferts are you dosing? I may need to step up ferts dosing? Maybe once every two days? What am I missing here? The tank gets phosphorus from the fish food. I couldn't think of anything else to dose.


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## DarkCobra (Jun 22, 2004)

Yep. More light amplifies everything. Growth, reds... and especially problems.

I'm dosing dry ferts, EI-style. Except I dose little or no KNO3 or KH2PO4. I keep my tanks heavily stocked with fish, they generally provide all the nitrate (NO3) and phosphate (PO4) plants need. And if I dose unmodified EI on top of that, I get ridiculous excesses like 100ppm nitrates, which is high enough to stunt plants, cause algae, and fish don't like it either. Of course I still need to dose plenty of potassium (K), fish food doesn't have much at all, so I replace what would normally come from KNO3 and KH2PO4 with an equivalent dose of K2SO4. I use no substrate ferts and basically inert substrates (usually Flourite), the fish produce plenty of mulm for plant roots instead. Maybe a few root tabs would help, I don't know if mulm is 100% nutritionally balanced; but then plants would be feeding more on that, and I'd be vacuuming more mulm.


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## 32Bit_Fish (Jul 8, 2012)

Now I could see the pic of your tank and the DIY light fixture. Your tank is beautiful and I hope my tank would look like yours one day. Your DIY light fixture looks better than any commercial light fixture including Catalina. Mine doesn't not have the individual reflector, but just good shinny one. I see you put a small fan in the fixture to keep the temp cool. Very nice! Maybe you can make a fixture for me. LOL...:smile:

I've turned off one bulb and turned down CO2. So that means the algaes may started to die off, plants may get wrecked and the red plants (Alternanthera reineckii) will definitely paling, not even sure would survive under 39w of T5.

I guess I can dose less ferts, inject less CO2 with less lighting. Of course, feed fish less? I have been having this oily scum at water surface. I usually feed two or three times a day with flakes, colorbits. Frozen food on weekends. Overfeeding cause algae as well, right?


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## dmagerl (Feb 2, 2010)

I have never had CO2 kill algae. It stops growing and new algae doesnt appear, but the existing stuff has always had to be pruned away.


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## DarkCobra (Jun 22, 2004)

32Bit_Fish said:


> Now I could see the pic of your tank and the DIY light fixture. Your tank is beautiful and I hope my tank would look like yours one day. Your DIY light fixture looks better than any commercial light fixture including Catalina. Mine doesn't not have the individual reflector, but just good shinny one. I see you put a small fan in the fixture to keep the temp cool. Very nice! Maybe you can make a fixture for me. LOL...:smile:


Thanks! I have a build thread on the fixture, some unusual things were rolled into it, like dimming and control via computer.



32Bit_Fish said:


> I've turned off one bulb and turned down CO2. So that means the algaes may started to die off, plants may get wrecked and the red plants (Alternanthera reineckii) will definitely paling, not even sure would survive under 39w of T5.


Halving the light should definitely help.

CO2 is more unpredictable in my opinion. Sometimes 30ppm+ stimulates the plants and causes algae reduction. Other times it only seems to feed the algae. As a personal opinion based on what I see in my own tanks, I'd shoot for 0.5 pH drop (about 15ppm) in your new lighting conditions, this has proven to be a sweet spot for me.

And the Alternanthera should be ok, I have some in similar lighting. Not very red or fast growing, but it survives.



32Bit_Fish said:


> I guess I can dose less ferts, inject less CO2 with less lighting. Of course, feed fish less? I have been having this oily scum at water surface. I usually feed two or three times a day with flakes, colorbits. Frozen food on weekends. Overfeeding cause algae as well, right?


Depending on how much per feeding, that could be a _lot_ of food. Complex organics from breakdown of food and fish waste are suspected by some to be an algae trigger.


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## 32Bit_Fish (Jul 8, 2012)

It is a very long T5 DIY thread. I probably going to read it on weekends. But I doubt I have the knowledge and tools to build one. 

I feed my fish in the amount that they can finish within one minute. Majority of my fish are aggressive eater and the large rainbow always make a big splash when he charged to the surface to get food. So I wouldn't expect much left over food sinks to the buttom. 

The fuzzy algaes looks like cotton candy to me. Are they going to go away under the reduced lighting? The tank water seems clear out and less surface scum. Maybe these are the signs that the tank is maturing?


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## aman32 (Jan 31, 2014)

My planted tank had scum on the surface in the beginning. Surface agitation and water changes got rid of it after 2 weeks or so. I think it was just bio mass from the new plants.


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