Auto Water Changer??

[SteveMM62Reef]

I’m looking to get away from the buckets. I have Peristaltic Pumps**, but I can’t get a single motor to drive two pumps. Looking for a DIY, set up I can set a timer, and do a water change in under three hours. Will not cost an arm and leg. 24 Gallon would be ny maximum water change volume. Don’t want a WiFi connection, as I’ll be doing other maintenance at the time, so I can monitor. **The Peristaltic Pumps I have are salvaged off of Cooling Tower Chemical Treatment Systems. We replaced the pumps when they got to a certain age.

 

[Quietman]

Without rigging up some complicated tank/float switch setup, I think that if they're the same pumps it's gotta be close to same flow rate. Just put on same timer and see how it works. I'd check salinity sometime after the water change for a double check as that's not going to be as reliable as a ganged pump but should be good enough. If you find consistent low or high, adjust timing on one or the other (or just add/remove a bit). Salinity in shallow water isn't rock steady on a reef after all (river run off, storms, currents, etc) so if not too drastic can take it. Your only issue would be if one fails - and even then, either your tank gets a bit low (no sweat) or you overflow (which you can back up with a float/leak detector into power source - various OTS and DIY).

 

[Dennis Cartier]

The normal way of approaching this is to use Masterflex pumps and heads. Their pump drives easily drive 2 of their heads. Another way is using Stenner dual headed pumps. The Masterflex are quiet and more flexible than the Stenner's, but the Steener's are built tough and will last forever. They are also cheaper than the Masterflex (even used).

Hmm, now trying to re-use your pumps. I would probably go for something that had a reservoir with a float switch and a drain with an automated 3 way valve. I would have a micro controller run one of the pumps to fill the reservoir with tank water until the float switch trips. Then the 3 way gets moved to drain the reservoir to waste. Then the 3 way is reset to closed, the second pump is ran to fill the reservoir with new saltwater. When the float valve trips, the 3 way is moved to drain the reservoir into the tank. Complicated yes, but the flow rate of the salvaged pumps will not be an issue.