Strange question?

colinsk

colinsk

On the fringe...
Dec 18, 2008
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0
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Ca
www.designerinlight.com
I am ditching my Hang on Back filter. I decided that filtration is not doing anything for my tank except driving off precious CO2. I do want to keep water moving. What is the best way to keep water moving in a 29 gallon tank and not suck up anything alive?

The gravel and plants are easily able to keep with the bio filter requirements.

After one week with no filter and no water changes:

0 Ammonia
0 Nitrite
5 Nitrate
7 KH
pH 7.6 in the mornings and 7.8 in the evenings.

Ditching the filter lowered the pH by .2. I was hoping it would lower it more but I have no CO2.
 
moving the water will gas off CO2. but if you are not adding CO2 via injection then you are not going to off gas CO2 using a filter... you will add CO2 thru gas exchange(which happens on the surface),,,moving water is better at exchanging gasses.
 
The fish are adding the only CO2 I have and I don't want it to off gas before the plants can use it but I do want nutrients to be moving acros the plant leaves. I think the fact that my pH changes when I change the water flow tells me disturbing the surface is off gassing CO2. Right now I have a really choked down powerhead moving water but the surface is perfectly still. This has lowered the pH .2 and kept the KH the same.

Is there very small power heads?
 
Colin, the fish are not your only source of CO2. There is some CO2 in the air that we all breathe. If the surface gets adequate movement, the CO2 in the water will reach equilibrium with the atmosphere. That is more CO2 than you would get just from the fish. I'm afraid you have used a model of what is going on that is just too simple to give the right answers. Star_Rider is exactly correct, removing the surface disturbance is hurting your CO2 balance, not helping it.
 
yhbae said:
What is exactly does this tank look like? Is it mostly low-light planted tank with very few fishes?
Click to expand...

Right now it is 2.6 watts per gallon CFLs, soil with a gravel cap and a few fish. Now that the tank is cycled I have some micro rasboras, pygmy corys and amano shrimp on order.

I am getting very rapid plant growth. The only fertilizer I am adding is fish food. I am planning to run the filter till I know the bio filter will stand up to the full stocking. I did find a very small powerhead at the LFS. It has worked out well. for keeping a current in the tank.

It is a prototye for learning the Diana Walstead planted tank method. She only runs a powerhead with no filter. I have the ability to add CO2 if I choose. I actually have three methods available to me. Pressure, fermentation and liquid. I am trying to not use them.
 
OldMan47 said:
Colin, the fish are not your only source of CO2. There is some CO2 in the air that we all breathe. If the surface gets adequate movement, the CO2 in the water will reach equilibrium with the atmosphere. That is more CO2 than you would get just from the fish. I'm afraid you have used a model of what is going on that is just too simple to give the right answers. Star_Rider is exactly correct, removing the surface disturbance is hurting your CO2 balance, not helping it.
Click to expand...

I am afraid you are right (you usually are). I will bring my pH meter home from work and see if I can get a better understanding of what is happening. I think my data set is too brief and has inaccuracies that are clouding my decisions.

I did find a very small powerhead to play with. Right now fish and plants are happy and no algae yet. I continue to get readings of 0, 0, 0 for my nitrogens so the plants are mopping up the Nitrogens pretty well. I am feeding like I have a full load of fish. While it is messy it is working so far. I should have fish next week.
 
Both star rider and Old man are completely correct. When you directly add Co2 to the tank your intentions are to dose more Co2 than what the equilibrium between your tank and the atmosphere is. Surface agitation gases off the excess Co2 before the plants can use it. But if you are not dosing Co2, a HOB or powerhead will actually help to add Co2, as star rider said through gas exchange.
 
I have to admire your desire to do a Walstead setup properly. In my case I refused to go completely without the filter. I use a sponge filter with a power head in my Walstead. It allows me to understand what is going on in the tank and gives me a backup in case I have plant growth problems. Meanwhile, the tank is doing quite well and is about a year old now.
 
My other tank is an attempt to model the "Optimum Aquarium" by Horst and Kipper. I guess that makes me more of a "mad scientist" than a fish keeper. :o
 
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