Interesting Case

[asylumdown]

This sounds exactly like what was happening to me when my water chemistry went weird.

a) what alk supplement is he using? is it baking soda from a grocery store, or something prepared specially for reef tanks? I know they're supposed to be essentially the same, but when I used baking soda, my water chemistry went haywire, and the ratios of solution made no sense. I also ended up with pumps failing weekly due to precipitation.

b) is he adding carbonate or bicarbonate as his alk source (carbonate would be if he's 'cooking' his bicarbonate)? With pH levels and dosing volumes both being that high, I suspect he's adding something with a lot of carbonate, which is considerably less soluble and more likely to precipitate out than bicarbonate.

c) It sounds like he's adding so much carbonate/bicarbonate that his levels are never balanced. Is he using an auto-doser? If he's pushing one past the 'limit', addition of the other will instantly react and precipitate out. I think you can get in to a vicious cycle. I bet at one point in the past he overdosed on one additive (likely alk), which caused a precipitation reaction that depressed his levels of calcium. On a test kit, it would have looked like he had low calcium and normal alkalinity. If he's using a doser, he would have then upped the amount of calcium he was adding every day. However, there would still be excess carbonate being added, so the precipitation would continue, and appear to depress his alk levels. So then he upped the amount he dosed alk, which would depress the calcium levels again... so on and so forth, always upping one, seeing a drop in the other, upping it, then seeing a drop on the other side. The end result would still look like he has 'normal' levels in his water, but that's because massive amounts are instantly precipitating out on pumps, etc. If this is the case, he needs to start dialing back on the amounts he's adding in the same way he upped his dosing volumes.

In either case, there's no other answer, he's adding too much. That's the only explanation for the precipitation. The 'normal' levels he's seeing aren't 'normal' at all, they're what's left over after the precipitation of the excess he's added to the system.

[asylumdown]

To add:

If you're finding that you're adding twice as much alk as calcium and you keep upping the amounts of each, I think you should first try dialing way back on the rate you dose alk. It seems counter intuitive, but if you're precipitating out large amounts of additive due to an imbalance, you're not likely going to see normal levels in one, and way high levels in the other, it will look like 'normal' levels of the one you're over-dosing, and low levels of the other.

[sphelps]

Originally Posted by asylumdown

This sounds exactly like what was happening to me when my water chemistry went weird.

a) what alk supplement is he using? is it baking soda from a grocery store, or something prepared specially for reef tanks? I know they're supposed to be essentially the same, but when I used baking soda, my water chemistry went haywire, and the ratios of solution made no sense. I also ended up with pumps failing weekly due to precipitation.

b) is he adding carbonate or bicarbonate as his alk source (carbonate would be if he's 'cooking' his bicarbonate)? With pH levels and dosing volumes both being that high, I suspect he's adding something with a lot of carbonate, which is considerably less soluble and more likely to precipitate out than bicarbonate.

c) It sounds like he's adding so much carbonate/bicarbonate that his levels are never balanced. Is he using an auto-doser? If he's pushing one past the 'limit', addition of the other will instantly react and precipitate out. I think you can get in to a vicious cycle. I bet at one point in the past he overdosed on one additive (likely alk), which caused a precipitation reaction that depressed his levels of calcium. On a test kit, it would have looked like he had low calcium and normal alkalinity. If he's using a doser, he would have then upped the amount of calcium he was adding every day. However, there would still be excess carbonate being added, so the precipitation would continue, and appear to depress his alk levels. So then he upped the amount he dosed alk, which would depress the calcium levels again... so on and so forth, always upping one, seeing a drop in the other, upping it, then seeing a drop on the other side. The end result would still look like he has 'normal' levels in his water, but that's because massive amounts are instantly precipitating out on pumps, etc. If this is the case, he needs to start dialing back on the amounts he's adding in the same way he upped his dosing volumes.

In either case, there's no other answer, he's adding too much. That's the only explanation for the precipitation. The 'normal' levels he's seeing aren't 'normal' at all, they're what's left over after the precipitation of the excess he's added to the system.

I believe he is using baking soda which he bakes in the oven first. I agree this is the likely the main issue, adding 10x the recommended dosage of this is going to cause a lot of precipitation which builds up on his equipment. The addition of Kalk is likely a factor as well which eats up all the CO2 in the tank, great for keeping algae growth down but not so good for dissolving all the additives.

[sphelps]

Originally Posted by Lance

Does the sump chamber where he doses have fairly low flow, or is he dosing the calcium and alk too soon to each other? I had the same problem for awhile in the 90g, (though not as extreme). I use the same recipe, and found if I dose the calcium and the alk into the same chamber I have to make sure there is at least 6 hours between the dosing times or I get calcification. In fact the water in that chamber was even a little milky from the two reacting together. I eventually moved the calcium dosing line to a different part of the sump that has more flow and that helped a lot. Within days after doing this the volume of calcium and alk I needed to dose to keep parameters in line dropped considerably.

Not super low flow, it's a decent size sump but the mag 1800 is running at full open so the sump turn over rate is pretty high. The alk is being dosed automatically along with the kalk top off but calcium is added manually each day. I believe the full 400ml is added at all at once which could be an issue.