Originally Posted 16-March-2009

Well the system is cycling. Ammonia has dropped to zero, Nitrites are off the scale and so are Nitrates and it is Day 19. I use a 5 in 1 test strip + ammonia and a Total Dissolved Solids meter. It's not super precise but it works.

Also, I'm having a real struggle with the temperature control. A water heater control is just not designed to keep accurate temperature. I've ordered a thermostatic control that opens/closes a 120 volt circuit. I'll connect a 24 Volt AC converter and plan to put a sprinkler valve in return line that will open when the temperature falls below 72 degrees, it will open the line into the water heater and push hot water into the fish tank until the temp rises.

My only concern is that the bypass line will remain open as well, (I don't have sprinkler valve that works in the opposite direction). It may be that the bypass line with lower resistance, will continue to bypass and no water gets out of the water heater. Anyway, later this week, when the thermostat arrives I will test it.

A day later:

System Cycling - High PH
I wasn't sure of this 5 in 1 test strip, so I went out and bought the regular kit that uses all the drops. Turns out my PH is 8.0, Nitrites are 5 and Nitrates are 10.

PH is going to be a problem I can see. I have some Phosphoric Acid left over from another greenhouse project. I'll add 1/4 cup and see how that affects the system.

The next Morning:

Bad Bad Bad! Koi dead.
This morning (8am) I added 1/4 cup of phosporic acid and 8 hours later it had not changed the PH at all, so after some reading, decided to add 2-3 cups worth (aprox 1/2 litre). I added it to the sump so it would mix.

At 9pm I went back out to test and see what it had done. DISASTER! my 4 Koi were dead!

I tested the water. PH had dropped to 6.0, Nitrites are 5, Nitrates are 10.

Note to the file: Fish do not survive big PH swings, adjust slowly!

Hopefully my plants will survive. I'll retest in the morning and see if the system is migrating back to normal.

Another quick note: A PH of 8 helps the system cycle faster, its the plants that dont like it. Don't worry too much about ph until the system finishes cycling. High PH will help it cycle faster.

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