Let me share my stupidity...

[sn4265]

Just recovered from a near disaster with my 120 gal mixed reef. In a nutshell, my durso standpipe had become completely clogged with algae and other growth. My tank NEARLY overflowed, and unfortunately I did induce a .2 pH swing since my ATO pumped in about 4 gallons of extra saturated limewater.

Turns out that those standpipes need to be cleaned on occasion. Maybe once a year or so since my tank has been up and running like 3 years without my ever touching it.

Just a friendly reminder to everyone. Don't neglect to occasionally cleanout your drainpipe setup.

I'm just seriously glad it happened while I was at home and not about 4 days ago when I was on vacation 1000 miles away.

[inetmug]

Happened to many folks as I read.

Many plumb the secondary overflow pipe in you have the space to solve this. It is the best way I can see.

What is "extra saturated limewater" for an ATO?

[1fishkeeper]

That is a great point to make. I have done mine once a year when I do a full cleaning. For a full cleaning I will drain the sump and clean it out all the way clean the pumps really good and anything else that I can see that needs to be done.

[footballdude2k3]

Good learning experience, do you have any shutoffs with a controller in case there's a leak?

[ca1ore]

Unless under duress, I would NEVER again run an overflow system with just a single drain. Too many things to potentially go wrong to risk it. Side benefit of dual drains (or even triples) is you can run one as a siphon and completely eliminate any overflow noise. Any system that requires regular cleaning to avoid performance failure (as opposed to just not working as well) is to be avoided.

FWIW, even with Kalk water for the ATO, salinity dilution is more of a problem than pH.