Low Tech Direction and assistance needed

steve worcester

Junior Poster
Oct 18, 2007
I would like some dosing and fert/trace suggestions.

I have a 1.75w/gallon 120G with a eco-complete substrate. Run an Ehiem filter in one corner with a power head in the opposite, about midwater. Run the lights about 9hrs day. It has been up about 8 months.
It is heavily populated with very happy mollies who are prolificly breeding.
The ph about 6.5, Nitrites 0, nitrates 20 mg/l, according to strips, GH 180 KH ~180.
I started with swords that were melting rapidly and thin anacharis and was doing water changes (which I have all but eliminated) about %25 weekly.

Anyway, started dosing potassium nitrate at 5/8tsp and monopotassium phosphate at 1/8tsp and Seachem equilibrium at 5/4 tsp all per week.

Then I got an Instant Ocean Phosphate and Nitrate kit. I noticed Phosphates over 5 mg/l and NO3 at 80mg/l!. Since then (4 months) I quit adding the phosphate and nitrates, used Nitrazorb to get it down to about 1mg/l, and the nitrates are down to about 20. I only feed about 1/day or 1 every 2 days

The duckweed has come back in full force, wysteria is growing ok, but curly and stunted with dark (algaeish) edges. Anubias has spot algae but has had new growth, the crypt. lutea seems to be real dark , almost brown/green. Rosanervig is growing, but again curled under and oddly formed leaves with algae edges. The anacharis is booming with only the older growth thinning. Swords are still thin, slow growning.

I know I am missing trace, because of only top offs and filter cleanings. So I need a suggestion on trace elements. Also, should i be adding some iron or something else here? I know I am missing something, but my rookyness can't filter through it.

All help is greatly appreciated.


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Sacramento, CA
When you use a test kit to guide your actions on almost anything, the first thing you should do is calibrate the test kit. You can't rely upon any test device or kit you purchase or make to be accurate without calibration. Since you decided to use a new test kit to guide your fertilizer dosing you need to make a few water solutions with known ppm of nitrate and phosphate in them. Then use those to make sure the test results are what they should be. Many people have found those test kits to be inaccurate, and very much so.

Years ago when I worked for NASA, I was amazed that no test device of any kind, no matter what the cost, was ever assumed to be correct. We always spent more time verifying that they truly were correct, and usually making calibration charts, than we ever did actually using those test devices. Even when we purchased pressure gages, with super accuracy, to be used to calibrate other pressure gages, we first had to calibrate the super accurate test gages - sometimes excruciatingly difficult to do. I learned a lot from that.