Problems with water changes and calcium reactor

gobble

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I've been using a calcium reactor for almost 2 years now and am having trouble maintaining calcium. I use the Alkatronic to maintain Alkalinity around 8.5, but have had a few instances where I check calcium (after I have a coral start bleaching) and find it as low as the 200's!

I think the problem is water changes and NSW. If I look at Instant Ocean, which I was using, it mixes at 400 and 11. If it's as simple as 8.5 / 11 x 400, I'm adding NSW at a calcium level of 309 when it moves down to the 8.5 alk that I'm maintaining. Reef Crystals is just as bad at 490 and 13, working down to calcium of 320 at 8.5 alk.

What's the solution? Do I really need to boost calcium in my mixing tank if I'm using a calcium reactor?
 
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gobble

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By the way, if I need to get my Reef Crystals in my mixing tank up to around 650ppm calcium to maintain 420 when the alk falls from 13 to 8.5, that's about 1050ml of liquid calcium chloride I need to add to every 65 gallon tank of NSW. Doing 65 gallons of water change with freshly mixed Reef Crystals would set me back 1050ml of calcium dosing if I was using dosing pumps. That seems hard to believe.
 

Dennis Cartier

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I also run a calRx and use an Alkatronic. Are you using the Alkatronic to dose alkalinity when it detects alkalinity falling below your preset range? If so, and if the Alkatronic doses alkalinity on a regular basis, the result would be to lower your calcium and magnesium in relation to your alkalinity. Personally, I have my Alkatronic set to not dose anything and only use it as a guide for me to adjust the setting of my balanced supplementation methods (CalRx and Kalk reactor).

As for your NSW, the normal way would be to lower your alkalinity to match the tank, and not try to boost the calcium. So if your salt mixed up at 400 and 11, you would drop the alkalinity to 8.5, which would leave your calcium at 400. Ditto for Reef Crystals, 490 and 13, lowering the alkalinity would leave your calcium at 490. The normal method of lowering alkalinity in NSW is to add an acid to decrease the alkalinity and aerate the NSW. This leaves all the other elements unchanged and just affects alkalinity.

Are you mixing your NSW to 35 ppt or 1.026? Your description of lowering the alkalinity to 8.5 and thereby causing calcium to be much lower, makes me think that you might be attempting to hit an alkalinity of 8.5 in the NSW by mixing up less salt and get the resulting NSW to come in at 8.5. Doing this would result in much lower salinity NSW, with all the other elements lowered, including calcium. You always want to mix to mix to full salinity and only adjust the specific element. In this case lowering alkalinity and leaving the rest at the normal level.

Another option is to just switch to a salt that mixes up to your preferred alkalinity level (8.5) when mixed at full strength. Personally, switching to a salt that gives you an alkalinity that you are comfortable with running your tank at, and not having to adjust your NSW to match would be far easier than having to adjsut every batch of NSW.

Dennis
 

Randy Holmes-Farley

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I've been using a calcium reactor for almost 2 years now and am having trouble maintaining calcium. I use the Alkatronic to maintain Alkalinity around 8.5, but have had a few instances where I check calcium (after I have a coral start bleaching) and find it as low as the 200's!

That sounds like it is test error, not a real result, unless as noted above you are adding alkalinity.

If it is real, just boost it with calcium chloride when needed.
 
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gobble

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Thanks for the feedback. I'm mixing the NSW to 35, not boosting anything in it, and am not manually dosing any alk with the Alkatronic.

I don't think it's test error because I tested with both Red Sea and Salifert and get a normal reading when I test the NSW. I just went through tank transfer method in quarantining some new fish, taking water from my display and replacing it with fresh made water. I probably went through 100 gallons of water and saw a coral start bleaching yesterday. So I tested and my calcium was under 300.

My theory is that if I'm adding NSW (with water changes) at an alk level of 13 the calcium reactor needs to add less to maintain my 8.5, so the calcium falls significantly as a result. I guess I should find a salt that mixes close to my desired parameters without an amped up alk level?
 
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Randy Holmes-Farley

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My theory is that if I'm adding NSW (with water changes) at an alk level of 13 the calcium reactor needs to add less to maintain my 8.5, so the calcium falls significantly as a result. I guess I should find a salt that mixes close to my desired parameters without an amped up alk level?

If by NSW you mean new salt water (usually it means natural salt water), then if the alk is 13 dKH and the calcium is 420 ppm, then if the alk drops to 8.5 dKH (4.5 dKH drop), calcium will not drop by more than 32 ppm.

Thus, that's not an explanation of how the calcium gets below 300 ppm.

But in any case, if you actually believe the result of low calcium, just boost it with calcium chloride.
 
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gobble

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Thanks. I meant new salt water, didn't know that meant sea water.

I guess I'm running to buy new test kits today.

I was hoping to do away with dosing or supplementing when switched to a calcium reactor. I guess set it and forget it doesn't work here.
 

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