Dosing ALK got froze in on position, but Lowered the ALK?

[Juiceman]

I have a dosing pump on a timer for my ALK and Calc that was maintaining my ALK at about 10 and my CALC at about 450.

Well yesterday the timer froze in the on position and dumped my entire half gallon of BRS ALK buffer and about 3/4 gallon of BRS Calcium solution into the tank.

When I got home, everything was covered in white dust, etc, so I cleaned all the filters, and pumps, and did a 20g water change.

I tested the water today this was the reading

ALK 7.5

CALC 500

MG 1400

I used the same salt I always do at the same SG, so It shouldn't have dropped it that much.

Could the ALK and CALC overdose actually caused a drop in the ALK? Why?

[FarmerTy]

Just off the top of my head, but I would imagine that the calcium and alkalinity that got dumped into your system precipitated out of solution and that's the white stuff all over your rocks. The alk probably lowered because the percentage of alk being removed during the process of precipitation is greater than the amount of calcium, slowly dropping the ratio of alk to calcium you have in your system.

That's my wild shot in the dark for an explanation this late without researching it.

-Ty

[Timfish]

The water can only hold so much of the buffering components that make up Alkalinity and Calcium so when you get saturation something has to precipitate out like JeeperTy said, Here's an article I like: http://www.advancedaquarist.com/2002/11/chemistry

I would think your tank is going to be OK but you need to watch it carefully that none of your animals got to stressed by the sudden changes. And as always water changes are a good thing.

[Juiceman]

That's what I was thinking, I made a point to do a water changed as soon as I figured out what happened. Fish seem fine, ate great the following day, Corals look good too, exept for the ones that were already doing bad.