# Water Changes in Low Tech Tank



## wrizviuva (Apr 5, 2015)

Hi,

I am starting with my low tech tank, and am using the Sudeep Mandal's Non-CO2 low tech planted tank, except that I am going for medium plant density, as opposed to high. For this reason, I am still doing 25% weekly water changes.

I understand that these water changes will result in CO2 fluctuations, but fish health is a priority. Curious to know what people think about this.

The setup: 15g tank measuring 23 (L) x 12 (W) x 13(H). 15W GE daylight light sitting at the top of the water. Fluval stratum substrate approx 3 cm high.

Plants: Crypts, Java Fern, Anubias nana, hygrophilia, rotala, Corkscrew val, and dwarf sag.

Ferts: Tom Barr's EI method for low tech.


----------



## Diana (Jan 14, 2010)

You could fill a bucket the night before and let the tap water stabilize, whether it gains or loses CO2. Then it would be more like the tank, less CO2 swing. To do this faster add a bubbler or small pump to circulate the water.


----------



## wrizviuva (Apr 5, 2015)

Thank you Diana. Do you recommend sticking to once a week fertilizers with water changes, ro should I increase to twice a week.


----------



## Freemananana (Jan 2, 2015)

I do a 30-50% water change on my low tech tank every week. It really isn't much more work to change a bit more water. As for the CO2 fluctuation, I've yet to have any issues and my plants have been doing fine. I'd say I'm medium plant density. I use a single EI dose on my tank after water changes.

Saturday 30-50% water change.
Saturday Macro dosage.
Sunday Micro Dosage.
Occasional Excel dose if I feel like it.

I haven't had any algae problems until just recently. I upped my lighting to nearly double and cut my photoperiod down. I just didn't back the photo period down enough. Easy fix for me personally.


----------



## Raymond S. (Dec 29, 2012)

Go/w whatever Diana says, just adding my sort of low tech 10g regime for comparison.
I have a bit more than low light/w 1 T5 bulb instead of 1 T8 bulb.
I use one dose per week of the regular level of EI instead of three of them.
I also add 2x the recommended amount of Excel per day.
There is an EI low light/weekly version which is used once a week and has a bit more
added to it for that reason.
But these state that a 50% water change per week is required. Excess build up will
occur if you don't.
I have been having a strange problem/w my plants in there for months.
By changing various things I have only two left to try.
I can use two doses instead of just one. The version that they call EI low light/weekly
has more in one dose than one of the regular EI doses for the same tank.
I could also just switch to that instead of doing two of the regular.
The level of light suggest it's not that But it's fairly obvious that something is lacking for the plants. I think this is sufficient info just in case your plants seem more slow growing than normal which is the case/w mine.


----------



## wrizviuva (Apr 5, 2015)

I will follow Diana's advice on filling the bucket the night before, and stick to 1x macro and micro.

I am also thinking of adding a reflector to increase my PAR value.

So far, I've never dosed excel.


----------



## Raymond S. (Dec 29, 2012)

I add foil on top of my lights. It makes a difference I can see when I put in on there.
You can just make a "tent" with the top of a "V" shaped piece/w the ends on the top of the tank.


----------



## philipraposo1982 (Mar 6, 2014)

I do 2x 50-60% WC in my 75g a week.


----------



## burr740 (Feb 19, 2014)

Not sure I buy the theory that water changes in a low tech cause co2 to fluctuate enough to cause algae. Maybe if the tap water contains an unusually high concentration, but normally we're talking about 3 ppm or so, and that's before a good bit off gasses due to filling/pouring, etc. That's just not enough swing to make a difference imo.

I've had two heavily planted low techs going for about a year now. One is borderline too much light. I do ~30% once a week or so and never had issues from it. The plants like it. The fish like it.


----------



## Miss_Goldie (Sep 13, 2014)

I feel your pain about fish health being a priority. I have goldfish in my low tech, heavily planted tank and the question is how to balance plant and fish health. 

I do weekly 50% water changes on my 75 gallon. As for the refill, I use a spare tank to age the water for the week. I have soft to moderately hard water so I use aragonite sand and crushed coral to buff it. I also have a bio-filter which help remove the ammonia in my tap water. And, the tap has supersaturated gases that cause micro bubbles if I add it directly to the aquarium so aging helps get rid of that too. I definitely agree with Diana, set the water aside. But, if you have other issues with your tap like I do it might help to set up an aging vessel and pump water from it instead of directly from the tap. 

I was worried about the plants initially because of fluctuating CO2 but after 6 months with no issues I think it is fine.


----------

