All,

Recently setup a 20 gallon non-CO2 tank. The tank has been setup for 4 weeks now and has been showing 0 ppm Ammonia for 1 week after cycling. I have been doing water changes often due to yellow water. I know that with a non-CO2 tank we are not supposed to change the water in order to maintain a consistent CO2 level; however this is the only way I have been able to keep the water clear.

I have 36 Watts of PC lighting.
3/4" of leonardite capped by 2" of Onyx Sand.
Plenty of plants.

Is the yellow water due to algae outbreaks, or is the leonardite causing the discoloration?

Should I continue to do water changes, or do I need to stop these immediately? Any other suggestions to keep the water clear? I have a HOB filter rater for 60 gallons running in the tank. It has plenty of carbon and zeolite for filtration.

Plants looks quite healthy. Some algae on lower leaves that is easily rubbed off.

Thanks,
John