raising tank alkalinity with calcium eactor

dendrite

New member
I have a heavily grown out 180 gallon tank with a 60 gallon sump. The corals are predominantly SPS/ acropora with large brain and hammer corals on the bottom. My problem is the calcium and alkalinity demands result in trouble maintaining a dkh above seven. I have an MRC c-1 reactor with a panworld-10 pump for internal circulation and a peristaltic pump driving the system . The effluent flow is 100 cc/ min, and I've lowered the pH to 6.2. I would hate to start supplemental dosing. Any adjustment advice would be welcome
 
I don't have much experience with calcium reactors, so we'll see how much I can help. Have you checked the dKH of the reactor output? That might be an interesting data point.
 
Bertoni is correct, check the output DKH. You do this with an alkalinity test & using as much reagent as needed, adding up multiple syringes to get the total. There is a minimum
needed for the unit to work.
I am going to find the thread & link it in another post.
 
not sure if anyone recommended this. but check you Mg levels. Raise to 1300-1400... I like to maintain it on the high side of normal.
 
Low magnesium can cause precipitation, but that causes loss of calcium and alkalinity in the form of calcium carbonate, so it's probably not the issue here.
 
Thanks for the responses. I did check the output and the DKh was above the limit of the Hanna checker at least at 16.8. I do supplement Mg as I have all along and that stays about 1400. I lowered the pH cutoff to 6.1 and increased the CO2 as well as increasing the flow . I will see what that does over the next several days, and whether or not the numbers hold after raising the alkalinity to 8.5 and the Calcium as well with supplemental dosing. I do love the calcium reactor and would hate to have to supplement dose the reactor. The reactor is rated for a 300 gallon tank but we all know what those ratings can mean.
 
I would try diluting the sample and measuring it. Maybe 3 parts RO/DI to one part tank water would be a good starting point. You could consider increasing the flow without changing the pH. I am worried about the pH getting low enough to cause problems with the media.
 
Tweaking more than 1 parameter @ a time can get you into trouble.
Which one worked or did not work?
You have to know the DKH of the output. If the test you have now can't do it get a Salifert
& just add the numbers from the tritration syringe.
Please read the link I posted above, it straightened me out easily.
 
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