dosing strategy, planted, low light/tech tank nearing end of fishless cycle



I am entering the 47th day (nearing the end: nitrates to 0 in 19 hours ;ph steady at 7.2 to 7.6) of a fishless cylce in a 29 gallon, 30 in. long tank, moderately to heavily planted in Seachem Fluorite (more arriving tomorrow) with 3 or so handfuls of floating plants, a HOB 350g/hour filter, a large piece of Indonesian wood (boiled for ~ 45 mintues), no co2 and one 55w CF (AHSupply) fixture, which I’ve run 10 to 12 hours a day on a glass top which blocks about 15% of the light, according to AHSupply.

I have done 4 water changes, none more than 50% and washed the filters in old tank water twice. My plants are not flourishing; some have died, others are hanging on; some have grown. I, also, have a powdery, light brown substance – algae? – on the wood and the plants which I remove with a tightly woven net every 4 or 5 days.

After reading through some of Tom Barr’s reports and articles in this forum I will I start fertilizing this tank tomorrow and reducing my light period to between 8 and 10 hours. After planting tomorrow and a 50% water change, is this is a dosing strategy you would recommend:

1.5 ml Seachem Nitrogen 2x per week
1.5 ml Seachem Potassium 2x per week
2.5 ml Seachem Phosphorus 2x per week
5 ml Seachem Excel 3 times per week
3 ml Seachem Flourish 2x per week, not on days when macros are dosed

Once the fish are in, should I maintain these levels, if these are the right levels?

Does all this sound about right? How often and how much of a water change would you recommend that I do? Any observations or questions?



dosing strategy, planted, low light/tech tank nearing end of fishless cycle

I'd like to add that my goal is to have a clear-watered, healthly, slow growing planted tank.


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Sacramento, CA
You have about 75 micromols per m squared per sec of light intensity at the substrate, your glass top is blocking about 15% of the light. I use that same light, located 23 inches from the substrate, and get about 50 micromols of light intensity. (45 gallon tank, 30 inches long.) Your tank is only about 17 inches high, so that increases the intensity by about (23/17)^2 compared to mine, and mine is open topped.

If you want low light, and I assume non-CO2, you need to raise that light about 4 inches. Also, the light should only be on for about 8 to 10 hours a day to minimize the algae growth. You should be able to dose the Seachem fertilizers per the Seachem chart, and get the plant growth you want.


Vaughn, many thanks for your reply. I'll raise the light 4 inches. But, after I complete my fishless cycle, I want to buy a different top; perhaps an all glass top, thereby increasing the amount of light by 15%. So, I assume, then, to maintain light intensity at the substrate, I should raise the light 15% of 4 inches, or about .6 inches, to 4.6 inches. Is this right?

One more question. Should I expect the algae to disappear if I regularly dose Seachem's liquid ferts?

Thanks in advance,