How to fill a tank with a sump ?

[jake37]

I'm a bit confused never actually having had a sump and that is how do you fill it ? What I mean specifically - is i understand the steady state - water flows from the tank to the sump and from the sump to the tank. If the tank drains too fast it goes below the inlet and stops draining. If the sump fillls the tank too fast it hits the inlet safety pipe and flows directly to the sump.
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What i am having problem visualizing is when you do a water change and you start refilling the tank how do you know when to stop without watching the sump level (which seems kind of annoying thing to have to do) ?

 

[Rhyno8]

Here’s a pretty good explanation of the different types of overflows. https://blog.marinedepot.com/durso-herbie-bean-animal-overflow. As for re filling you will have to watch the tank refill Atleast the last portion. Usually you have a mark as a maximum fill line on the sump depending how you have it set up.

 

[pacu mom]

We have a wet/dry filter. Once the water level in the main tank is high enough to enter the overflow box, we start watching the wet/dry filter. When removing water, we keep the return pump to the sump running to remove as much water as possible, then turn the pump off. When the water level looks about right, we stop filling and turn the return pump on. When we do that, the water level in the wet/dry filter drops about 2-3 inches, and we add more water to the main tank.

Through the years, it hasn't been a problem for us. The bioballs in the wet/dry filter are not submerged. During a power outage, we added more water to the main tank to get the bioballs completely submerged to prevent beneficial bacteria die off. (With a whole house generator, we don't have to do that anymore, as it is always business as usual with the fish tank.) We have a 55 gallon tank we use as a holding tank for refilling the main tank. For us, if we want 3 inches more in the sump, we just pump out 3 inches from the holding tank to the main tank via the mechanical filtration plumbing.

With our big tank system which is not set up yet (longest tank upgrade in the history of fish forums) we will have hot/cold water lines to the 405 gallon sump tank and water lines 2 ft above the main tank. We will probably refill main tank and sump tank simultaneously. Removing water will be via the mechanical filtration system and purging the two Ultima II 4000s.

 

[duanes]

Your tank (if the pump is running ) will always stay full, its the sump water depth that will drop or rises with water volume.
I always try to maintain my sumps fairly full, I never want the pump to run dry.
Because my overflows are close to the surface of the main tank, during a power outage, the main tank will only drain a couple inches by gravity, only to that overflow point, So my sumps are maintained just about 3 inches below the sump rim, enough to handle a power outage gravity volume. I usually use tanks or 50 or 75 gallons as my sumps.

For me during a water change, I remove just enough water to maintain the running pumps intake under water.
This may mean 30 or 40 gallons in a 50 gallon sump, or more if the sump is larger.
Below a 75 gal planted sump, during a water change.

Below same sump normal water depth.

by the way when refilling, I never put new water directly into the main tank, but always into the sump, this helps gauge actual water volume.
And I use check valves with floats to help keep from over flowing the sump to the flopr

The red thing on the right is a float valve, as the sump is filled the float pinched water flow to the sump.
Below working, filling an Index kiddy pool.

 

[jake37]

That makes me sad. So you do have to watch the sump fiill line to put enough water in the tank. Sounds like a pia. I've read up on the different types of overflows but because they give them weird name and not simple names i always forget the actual names.

Here’s a pretty good explanation of the different types of overflows. https://blog.marinedepot.com/durso-herbie-bean-animal-overflow. As for re filling you will have to watch the tank refill Atleast the last portion. Usually you have a mark as a maximum fill line on the sump depending how you have it set up.

 

[jake37]

So you never do large water changes? I'm planning a 500 gallon tank with an approx 70 gallon sump but a normal water change would be 30% or ~130 gallons. maybe with larger tanks water changes can be smaller? In any event it seems like this is going to be annoying.

Your tank (if the pump is running ) will always stay full, its the sump water depth that will drop or rises with water volume.
I always try to maintain my sumps fairly full, I never want the pump to run dry.
Because my overflows are close to the surface of the main tank, during a power outage, the main tank will only drain a couple inches by gravity, only to that overflow point, So my sumps are maintained just about 3 inches below the sump rim, enough to handle a power outage gravity volume. I usually use tanks or 50 or 75 gallons as my sumps.

For me during a water change, I remove just enough water to maintain the running pumps intake under water.
This may mean 30 or 40 gallons in a 50 gallon sump, or more if the sump is larger.
Below a 75 gal planted sump, during a water change.
View attachment 1455769
Below same sump normal water depth.
View attachment 1455771

View attachment 1455770

 

[celebrist]

I drilled my sump to go to drain so overflowing the tank is impossible, of course I proved a few times that I needed to do this first, lol

 

[duanes]

So you never do large water changes? I'm planning a 500 gallon tank with an approx 70 gallon sump but a normal water change would be 30% or ~130 gallons. maybe with larger tanks water changes can be smaller? In any event it seems like this is going to be annoying.

This is one of the reasons I do daily or every other days water changes.
If the sump is too small, water changes can be limiting.
If I had a 500 gal tank, Id use a sump in around the 200 gal range.
Smaller water changes may work, if they are frequent enough, and that really depends on stocking levels, and nitrate concentration for me.

 

[Dave62]

I have a 110 gallon DT on a 30 gallon sump and do 30% WC every day (discus). I used to try to refill via the sump, but that turned out to be too much guess-work. Now, I just add the water directly back to the tank. When the water level in the tank reaches the bottom of the overflow weir inside the tank and starts to trickle back into the overflow, I am done. There will be about an overflow's worth of water in the sump (plus whatever was in the drain pipes) which will be returned to the overflow via the tank when I turn the return pump back on. (If you've set your sump up right, it will contain all the water from the overflow and drain pipes).
I pump the new water from my aging tank in the basement to the DT currently using a long hose. Working on a piping system through my crawl space, which will greatly improve the whole process.

 

[jake37]

I'll most likely get the tank from custom aquarium with one of their sumps. In some ways i wonder if it would just be easier to get an ultimate filter and skip the sump.