Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
So here are two ways to get the answer:
Set up a 'tank' (ie bucket, whatever) with the blend of RO + tap that suits your livestock.
Feed it just like you really had shrimp and fish in there.
Test with all the tests you have or can find.
NO3, P, K (maybe- I understand they are not worth much), Fe, GH, KH, pH, TDS
See what a non planted tank is like. See how these values rise through the week.
Then add a handful of plants. In a 5 gallon bucket I would have a couple of gallons of water and a double handful of hornwort or anacharis. Put a drop light over it. Maybe a glass lid or a screen to make sure the drop light does not drop into the water.
Continue feeding the virtual fish for another week or two and see what happens to the tests.
Here is the better way:
Set up the tank the way you want.
Cycle it, or at least add some nitrifying bacteria (Nitrospira species).
Add the more durable of your livestock.
Run it, seeing what happens. The plants themselves are your 'test kit' for many things.
I would test TDS, GH, KH, NO3 and maybe pH. Of course a new set up would need NH3/NH4 and NO2 tests until the cycle is complete.
When the tank is up and running, and the cycle complete:
Use the NO3 test as a stand in for N, P and traces.
If the fish food is supplying enough NO3 (it stays between 5-20 ppm, or else you have to do water changes) then you can assume the food is also supplying enough P and traces. (but not Fe)
If the fish food is not supplying enough NO3 (it keeps dropping, or barely shows up) then you can assume you need to dose NO3, P and traces.
Use the GH test as a guide to Ca and Mg. Unless you have a reason to think the Ca and Mg have a weird ratio out of the tank, assume that a GH >3 degrees and stable is just fine. If you think there is an odd balance from the tap water between Ca and Mg, then you will have to get a fresh water Ca test and figure it out.
Use the KH and pH tests to know that things are stable. I generally set the KH pretty much equal to the GH, then the pH is controlled by the carbonates or peat moss in the right range for the fish.
Use the TDS to know if salts and minerals are building up, and as a clue for a water change. Whatever they are to start with (you decide by blending RO + Tap water) you can see the changes over time. Usually the TDS rises, and you will do water changes to keep it stable.
Assume you will need to dose K, Fe and C. There is generally not enough K or Fe in fish food, and carbon is almost always needed, even a low tech tank can benefit from some carbon.
The plants will tell you about K and Fe. Look for pictures of deficiency in these 2 elements so you can see the earliest signs.