I must admit that I'm one of those aquapons that used to test the water quality religiously, every week, but have become much more relaxed about it of recent months.
With all the discussion on this forum regarding pH, and the timely reminder from Dr George that things do better if the numbers are closer to optimal, I decided a full water work-up was due.
Results: pH - 7.8, Ammonia - 0.25, Nitrites - 0.0, Nitrates - 20-40.
Hmmm - that's a lot better that I was expecting. My DWC bed has been overflowing over recent months, due to masses of roots in the outlet pipe (yes - I know, it's basic maintenance...), so I was topping up 50 gallons every couple of days which is about 10% replacement. I suspect that this directly impacted my water quality.
To adjust the pH, I dumped a cup of muriatic acid in to the radial flow filter. Normally I'd put this in the top-up 50 gallon drum, but since I've fixed my overflow/leak issue I don't need to top up. Once the acid has been through the filter, gravel grow bed and DWC bed before it arrives at the fish tank, it should be mixed and dilute enough not to worry the fish. I'll test again tomorrow and repeat the dose if required. Why 1 cup? That's from experience with my system. YMMV.
Ammonia at 0.25 doesn't concern me at all. I'd rather it be 0, but in the past I chased that holy grail only to find out that the test liquids were showing 0.25 on pure water, so I'm going to put it down as 'close-enough'.
Nitrites at 0.0. Perfect.
Nitrates at sub 40. Wow! Now that's a surprise. Every since I cycled this system over 18 months ago, the nitrates have been sky high. i.e. off the charts. Too many fish, not enough plants. Fair enough. But I added two grow beds, tripling the growing area, and the nitrates didn't really budge. Finally, after growing a serious jungle of plants, tomatoes and beans mostly, replacing 10% of the water every couple of days, and the cold weather stopping the fish from eating, the nitrates have dropped on to the measurement scale. I'm very, very, very happy with that.
Will I return to weekly water tests? Probably not. I'll get the pH to around 6.8 and then check every couple of weeks. With the water leak fixed, I don't expect rapid changes in water quality until the fish start eating again. Then I'll have to worry about raising the pH, not lowering it.
