Planted Tank Guru
Join Date: Dec 2004
Location: Skagit County, Washington State
Well, you can get the answers at Rexgrigg.com on dosing.
But here is a quick breakdown. There are micro (trace) elements and macro nutrients (such as nitrates, phosphates, calcium, potassium etc. that plants need. Some are usually in the water column such as calcium.
If its a medium light tank you might get away with just some potassium and trace elements every once in a while, depending on your fish load. If you feed enough fish, their extra food will take care of the phosphates and their excrement will cover the nitrates. You can buy all of these ferts on the cheap from a fellow hobbyist who sells mostly as a service, not for much profit - Greg Watson.com. His trace mix is called CSM+B. The other dry ferts are sold in one pound amounts. One pound of potassium sulfate will last a fellow a long time. I use to dose it around 1.5 teaspoons per 50 gallons of change water. Most of this is on Rex Grigg's terrific site.
And one needs to know about their water parameters, light wattage/gallon etc. to dose correctly. You'll need to test for nitrates and possibly phosphates. You might get away with just doing the potassium at water changes and adding a little bit of a trace mixture once or twice a week. It all depends on the amount and duration of light and if you have pressurized CO2 or not... Hope this helps and remember, better to under than over dose ferts. Just watch the plants.
Three Tanks...Eheim 2128 & XP3-90G, Eheim 2128-65G, Eheim 2232-25G.... Tek 4x54 watt T5-90G, Aqualight 96watt PC 65G low tech, 65 watt Aqualight-25G.... Hydors-90G & 65G ... Flourite in 90, 65, & 25 Gallons, .... Auto Water Change/Auto dosing on 90 & 65 gallon..... AGA member......