Is my DIY 75g sump designed right?

[ShowboatHK]

With a 150 display tank and 75g (not actual) sump I have a problem. Every couple days my return pump section of the sump runs so low that the pump draws air and sends bubbles to the tank. That section is rather small. (8” x 8” x 17”) I had hoped evaporation would be slower because of the size of the sump, but didn’t realize the small return section was the only area that would show the evaporation. Did I do something wrong?

 

[Brad Miller]

You want to let the auto top off (or do it manually) be a normal line maintained in the section with the return pump

 

[ShowboatHK]

Normal line?

 

[Brad Miller]

Every skimmer has a normal range of water depth to operate it at for best results.
The green marker lines are for my range on the skimmer.
I set my auto top off to maintain the water level in the return pump section, where it is running now.

 

[Fritzhamer]

Exactly, my setup is like yours although I run the fuge first. The only place you will see evaporation is the return section. I HIGHLY recommend an auto top off device to keep track of and replenish evaporated water.

You set it in the return section at the level you want the water to stay and it does the rest.

 

[Brad Miller]

Also keeps the tank salinity very stable with ATO

 

[ShowboatHK]

So my issue is normal? ATO is definitely on my short list of things to buy.

Also< thank you for th ereplies!

 

[Sod Buster]

ATO sensor always goes into the return pump chamber. Where you introduce the ATO water is a personal decision, some like the drain chamber, some like return pump chamber. Always the sensor is in the return chamber of the sump. That is the 1st to show evaporation, how sumps are built on purpose.

 

[Brad Miller]

Yup, normal it seems....
For now just put a piece of masking or painters tape on the outside of your return pump section of your sump and draw a line on the tape where you want your water to be.
Then just top off with RODI water to the line more often.

 

[Sod Buster]

The tape line needs to be right there

 

[Fritzhamer]

GMAC has a great site that talks about some of the ins and outs of sump design. You may have seen this but it may be helpful for others that find this thread in the future.