Alkalinity Swings in a Reef Tank

For me, its been a constant battle to re-automate my tank once I futzed with it.  The tank was doing well.  I had a 30g sump and 30g fuge in the basement.  But I couldn’t leave things along and wanted more total water volume, so I replaced those two tanks with 3 stock tanks.  I now have a 40g refugium and a 40g sump and a 50g frag tank (though it is mostly empty right now. They are all stock tanks and they have added to the complexity of my set-up.

Rose Millepora after alkalinity swing

For one, I can’t get the ATO (auto top off) to work properly.  If I leave it plugged in, it ends up flooding my tank.  If I leave it unplugged I have to remember to go downstairs every night and add fresh water.  This is not optimum for any number of reasons, but most of all it means swings in salinity in the tank.

My other problem is my calcium reactor.  It was behaving badly for the last 6 months and I just couldn’t take it anymore.  It had been off for about a month and then I realized I wasn’t adding calcium and my alkalinity was low.  So, i dosed with a 2-part solution and actually overdosed.  So my alk went from 7 to 12 and my calcium went from 330 to 480.  BIG MISTAKE

These shots were taken under the actinics, but you get the point.  Several corals are STN (Slow tissue necrosis).  I finally broke down and invested in the reactor I should have bought originally – the GEO 618.  I also replaced my solenoid and finally got it hooked up to my ReefKeeper Elite last night.

ORA Red Planet after Alkalinity Swing

I have to tell you this thing was a piece of cake to set-up.  Some assembly required, yes.  But then it just works!  The biggest difference between this and the prior reactor (I think) is the feed pump.  My prior reactor, an AquaC RX-1, did not require a feed pump.  That was one of the main reasons for buying it.  That, and the customer service of AquaC is awesome.  But, not having a feed pump means that there is a leveling issue.  The reactor can’t be too far above the water level and or two far below.  It requires precise positioning.

The GEO doesn’t.  It can go wherever and it just works!  So, I am now in the process of dialing it in and hoping that the corals recover.

Two lessons here:

1. Pay attention to reviews and listen to others.
2. Don’t do anything fast.  If a parameter gets out of wack, bring it back slowly.  Yes, we all know this, but it bears repeating now and then.

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