.Chris.
Member
So
Did some more tests tonight. Calcium and mag dosing seems to be dialed in. Holding steady at 460 and 1500 now. Alkalinity stability is there, but too low. It remains around 7.0 which I feel is too low for a high nutrients system like mine. I'd like to keep it around 8.2. I've upped the dosage by another 33%, from 60ml Red Sea Foundation B, to 80ml daily. Believe it or not, I started at a dkh of 5.6 when I got my dosing system online, and I went from dosing 8ml daily, which is what I calculated to increase kh by 0.5 dkh weekly. Apparently my aquarium is smarter than I am.
I borrowed a friend's Hanna phosphorous checker, since I am convinced it's more accurate than my Red Sea. I know part of my phosphate issue is my RODI unit. I haven't changed the membrane in over a year, and the last batch of DI resin I put in there less than a month ago has already been used up, and that's only the second time I've changed it in 15 months. So clearly soemthing was up. Finally got out the trust TDS metre...10 TDS after DI. Oops. Gotta check it more often. No clue how long this has been going on for.
Anyway, I'm sure that's not entirely the issue, but partly. According to the Hanna checker, PO4 is at 0.18. Fairly consistent with the 0.16 I was getting with my Red Sea, surprisingly.
RO water is at 0.11.
Interesting note though. I checked the out on my inline TDS metre, and it spiked all the way up to 30 before settling in at around 7. The way I top off my tank, the unit is directly connected to my sump, with a sensor and solenoid valve opening and closing my RO auto top off line (with a float valve failsafe). So each time my solenoid opens, TDS spikes to 30 for about 15 seconds, before dropping down to 7.
Could that TDS of 30 topping off my sump 4-5 times daily be part of the problem?
Also another interesting note, I got the exact same result as a friend of mine who just did the same test on his RO unit. And he has an identical unit as mine, bought at the same time from the same place. Coincidence, right?
Did some more tests tonight. Calcium and mag dosing seems to be dialed in. Holding steady at 460 and 1500 now. Alkalinity stability is there, but too low. It remains around 7.0 which I feel is too low for a high nutrients system like mine. I'd like to keep it around 8.2. I've upped the dosage by another 33%, from 60ml Red Sea Foundation B, to 80ml daily. Believe it or not, I started at a dkh of 5.6 when I got my dosing system online, and I went from dosing 8ml daily, which is what I calculated to increase kh by 0.5 dkh weekly. Apparently my aquarium is smarter than I am.
I borrowed a friend's Hanna phosphorous checker, since I am convinced it's more accurate than my Red Sea. I know part of my phosphate issue is my RODI unit. I haven't changed the membrane in over a year, and the last batch of DI resin I put in there less than a month ago has already been used up, and that's only the second time I've changed it in 15 months. So clearly soemthing was up. Finally got out the trust TDS metre...10 TDS after DI. Oops. Gotta check it more often. No clue how long this has been going on for.
Anyway, I'm sure that's not entirely the issue, but partly. According to the Hanna checker, PO4 is at 0.18. Fairly consistent with the 0.16 I was getting with my Red Sea, surprisingly.
RO water is at 0.11.
Interesting note though. I checked the out on my inline TDS metre, and it spiked all the way up to 30 before settling in at around 7. The way I top off my tank, the unit is directly connected to my sump, with a sensor and solenoid valve opening and closing my RO auto top off line (with a float valve failsafe). So each time my solenoid opens, TDS spikes to 30 for about 15 seconds, before dropping down to 7.
Could that TDS of 30 topping off my sump 4-5 times daily be part of the problem?
Also another interesting note, I got the exact same result as a friend of mine who just did the same test on his RO unit. And he has an identical unit as mine, bought at the same time from the same place. Coincidence, right?














