Which dosing strategy in low tech tank and limitations in light, CO2 and substrate



I only want to dose once about every two weeks and only want to do a water change about once every 4 months or so. What dosing strategy will work with that kind of a schedule, and what limitations will that strategy need in the context of light, CO2 (Excel), and substrate?

Tank & Fish
29 g, 30 in wide, 55W cf (AHSupply.com) raised 4 inches, an Eheim 2026 external canister, an HOB Marineland Penguin Power Filter 350B to be removed when the Eheim matures, fully planted in Seachem fluorite, one somewhat large piece of Malayasian wood (boiled for 1 hours before placed in tank). Fish: 6 Neon Tetra. 78F. I want to add a crossocheilus siamensis.

I added the neon tetras today - 11AM - after an extended fishless cycle. Until 2 days ago I dosed ammonia daily to 4ppm. After 12 hours, ammonia would go to 0; nitrites to 1ppm; nitrAtes to 40ppm. Until yesterday I had been using Seachem ferts as per Seachem's recommendations for macros, micros + Excel (2x to 3x dosing Excel to treat algae).

Yesterday I did a 90% water change and water clarity has improved; but is still somewhat green. Algae present are a bit of BBA, diatoms on glass and green water.

Today, I fed the fish at 2pm. At 9:30pm ammonia was 0; nitrites 0; and nitrates 40ppm; pH 7.2. I did not measure hardness.

I look forward to your reply.


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Sacramento, CA
A 55 watt PC bulb is too much light for a 29 gallon tank if you don't use CO2. If you raise the light about 6 inches it might be acceptable. Once you get the light down to acceptable non-CO2 limits, you should avoid water changes as much as possible, since each water change temporarily raises the CO2 level in the tank, and that fluctuating level of CO2 triggers algae blooms. You could poke a few fertilzer tabs into the substrate near the fastest growing plants and then only dose fertilizers once a week or every other week, or even longer between doses.

EDIT: Looking back at my data with a 55 watt PC bulb, I don't think raising it only 6 inches will be enough. I think I would start with raising it about 10 inches.

Tom Barr

Staff member
Jan 23, 2005
Maybe 2 x 24" bulbs 20W each, Normal T12 sizes etc, Triton brands, and that would be about it for this tank.

This is a non CO2 tank method for sure.

EI has no role here.
Read the non CO2 thread and reduce the light somehow..........

Tom Barr