Backyard Aquaponics
A place to discuss aquaponics

I am taking an aquaponics class, and we are doing a project on testing different water cycles. What would be the best two cycles to test?

If I read your question right, you want to know what substances to test for?
The most critical to an AP system are ammonia and Nitrite. They are also some of the first to show readings.
pH is important as it effects the toxicity of ammonia
Nitrate is not very important at all, so long as there is some.
Salinity (general hardness), and pH Buffering water hardness (Carbonate Hardness) are similar. They need to be there but they value is not critical.

And because ammonia toxicity is related to pH and water temperature... you'll want to measure water temp as well ...

Oh yeah... I knew I'd miss something!
If it's a running system, you will get results from Nitrate, pH, temp, GH and KH.
If it's a new system, ammonia and nitrite are the tests of interest, as they will show spikes as the bacteria colonise.
So it really depends on your definition of 'the two Best tests' and the status of the system you're testing.

Thank you, now we are also doing two separate systems and we want to try two different water cycle times and see how it affects the plant growth. Any suggestions for different times?

Ah! You are testing different flood/drain periods! I would say to use matched systems (all same components) to control those variables, then give one a minimal drain period (just enough to drain decently) and give another an hour of additional drain time. Measurable parameters might be plant growth, ammonia, nitrites, and system maturation (cycling) time.

Yes, if testing different cycle times...
Then one system that pumps till the bed is flooded (perhaps 15 minutes) and then give it only enough time to drain the bed. It will depend on the pump but you might test 15 minutes pump on and 15 minutes pump off if the pump is strong enough to fill the beds in that time even with enough drain holes to empty the bed in 15 minutes. Otherwise you will probably need to do 15/30 or 15/45. And the other system I agree would be good to give an extra hour or so drain time between floodings.

I would suggest that you might not see a huge difference between the cycle times very quickly. As in a two week trial with brand spanking new system might not show conclusive evidence of one being better than the other. Also, one might be better for different seasons or different plants. Certain plants like drier conditions or more dry time between watering than other plants. During really hot summer afternoons, most plants might like more wet time while during cooler or wetter seasons the plants might want more dry time.

anyway, will be interesting to see the results of your tests.

we are using a mature system and our experiment will be lasting about a month. Also though we are having two separate grow beds the water is coming from the same pond.