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Merfin70
10/18/2009, 02:11 PM
I had a tank crash while away on vacation. Now that I have it somewhat stabailzed, I'm interested to know what happened chemically. The cause was my calcium dosing pump falling off it's support, or so I think. The level in my alk jug was significantly lower than ca so I suspect the ca hose kinked when the support failed. So for 7 days all that was dosed was Alk. I returned home to all of my sps in advanced rtn. Testing showed an alk level of 16-17.

In the absence of calcium dosing the alk runs out of control? Or should I be looking for another cause. Not sure what I expected but with consistent alk dosing and no ca, guess I expected ca to fall off the cliff but not a huge spike in alk.

Randy Holmes-Farley
10/18/2009, 02:36 PM
If calcium drops too low, corals and coralline algae cannot calcify and so alk may rise if you keep adding alkalinity when it is not being depleted.

Have you measured calcium in the tank?

Merfin70
10/18/2009, 02:56 PM
I have not measured ca yet but will do so tonight now that the cleanup is done. My clean up crew was completely belly up so I've been in emergency mode removing dead snails and doing some significant water changed. Today I plan on testing everything so I can get the chemistry normalized again. I'm also going to turn on the dosing pumps.

Randy Holmes-Farley
10/18/2009, 03:14 PM
I'd suspect there may have been another problem too.

Merfin70
10/18/2009, 07:46 PM
I'm tempted to agree but cannot lay my finger on it at the moment. Whatever it was it happened quick or was something that had been building up over time. Almost wondering if the Ca pump had been off longer than my vacation. I didn't look under the tank for a week or so before vacation so it could have been kinked for 2 weeks+. The difference in the jug levels between Alk and Ca was about 2"s so I suspect it had not been working for some time.

Ran my tests tonight and remarkably, after having the alk dosing pump off for the week, I'm back down to an Alk of 8 and CA of 450. So I'm plugging in the Alk pump tonight to keep things stable. Likely I will have to back down my timing as my SPS are completely gone and so the tank will have fall less need than before.

Tank is an unfortunate mess of algae and brown slime that I suspect only time will heal. At least some of my LPS survived. My duncan is open again after a week and my Acans are starting to perk up. Corals are remarkably resiliant creatures for as much as we think of them as fragile.

Randy Holmes-Farley
10/19/2009, 05:59 AM
Could there have been a power failure while you were gone?

VacavilleFC3S
10/19/2009, 02:35 PM
hmm thats very odd, i don't dose CA very often at all just baking soda for my ALK, so i doubt just dosing ALK did that. are you sure that your ALK doser didn't malfunction and overdose???

Merfin70
10/19/2009, 06:47 PM
No power failure as my other house electronics were all good. If I have a power outage I can tell because the CD player lights will be on. As for a potential Alk overdose, I don't think so either as both dosing pumps are on the same controller channel via the same outlet pair. They can't work independently.

Not sure if this might confirm my dosing pump theory or lead somewhere else but I'm now remembering that for 1-2 weeks before vacation, I noticed that the Alk was "clumping" more than usual when dosing. Normally I get the cloud but this was more clumpy.

Hindsight is 20/20 but perhaps that should have been a sign that something was out of balance.