My Overflow/Return and Sump Project - Opinions sought

Hi all, first real post here (my intro is in the intro lounge

I have been studying the u bend overflow and sump threads here and built an overflow for my 5' tank which works as expected but with a couple of things to finetune.

I find that my pump - rated 3000L/Hr is too strong for the overflow and I have had to govern its return rate to stop the overflow pulling air. I will buy a smaller quieter pump today and hook it up - the 3000 was for water changes anyway.

I have used an airline non-return valve on the top of the first U to remove air and then once primed I run the end of the line to the venturi of the Otto powerhead to allow air and gas buildup to bleed out...

I do find the plumbing rather noisy... More so than expected. I intentionally followed all the points about gurgling and bouncing and ensured that after the T piece the plumbing goes from 40mm to 50mm.

Here are a couple of pics of the system installed and running to a 2' tank below which will be the sump - still working out the best design for this.






I hope to incorporate some mechanical filtration as well as a wet/dry design and will have questions about that part for sure.

My current filtration is a Fluval FX5 with three decks of siporax, a carbon bag and its resident sponges. Also the Otto 1200 for intank mechanical filtration which usually has sponges and a purigen bag in line.

I do wonder if adding a wet dry will really make a big difference since the current system is handling all the NH and N02 that I can measure - ie always undetectable - and the N03 must be combated with water changes anyway.

None the less I feel that any additional highly efficient filtration is beneficial with large fish (2 Oscars and 7 Silver Dollars) and I'm sure it helps with further dilution, aeration and mechanical and biological water conditioning.

I would love to hear thoughts and opinions on how I can improve and maximise my setup here! Thanks all.

Will

OK so I have put a new pump in - 2400lph and added a pot for bio balls and a drilled pot plant dish on top for a drip tray. I drilled it so it would hold a good level and rain on the bio media below - very evenly.

I then tuned the water level in the tank so it would take the sump if it pumped dry and so that the sump would take the tank in a power outage.

I tested it for power failure and it restarts fine too.

The gurgling has been fixed by putting a 90' on the intake and reducing the flow of the return pump.

Thank you fishdance for that insight.

I will need to mod the drip tray in the pot since it is filling a little too high. Fortunately that will simply mean that the rain in the bio chamber is more consistent.

I appreciate your comment on the overflow possibility and will put an overflow drain on the side of the media pot.

Finally, I don't quite understand the plumbing you allude to that could provide a secondary flow of the sump/overflow in the cases you mention...

Is this to isolate the sump tank from medication in the main tank - or to allow meds in the sump tank without returning to the main tank? I guess the former because meds will kill beneficial nitrifying bacteria won't they? WOuld that make the use of the sump tank as a quarantine operate in the opposite way to the medication situation. :? I can't even explain my confusion :? :lol:

Thanks for that - very clear diagram. I am still somewhat confused about the isolation condition. The outlet would have to be closed with a valve and the pump only re-circulating the water in the sump - right?

Good solution for a case where there is too much return and improves circulation in the bio filter too!

Ihave downsized the pump but only from 3000 to 2400 and I am finding the return more than enough so I could still make this modification

I have also pulled the system down and am rebuilding the sump. I got 3mm acrylic and setup the sump like this:

So the overflow drain ][ goes into a section of polyester wool or a filter sock (not sure yet) and then up to a spillway ~~~\ and the drip tray -----, through the bio media %%%%% which is 1/3 submerged and finally into the pump chamber.

I have calculated it so that the first stage holds around 18L and the second stage 16 at the right level. This means that in the case of a power outage the sump can accommodate the overflow based on the fact that for every 1cm of water level in the main tank is 7L and the overflow invert is an effective 2.5cm of volume = 17.5L. The sump will overflow on the inner walls in the case of some other failure or backup...

I think I have got most of this right but will have to wait until the silicon cures and do some tests on the bench first.

This will be far superior to the existing pot and dish system and I couldn't help myself.

The mess I have made of the internal fittings with my first attempt at building aquarium walls is appalling - seriously ugly but hopefully functional I hope I can clean it up a bit on the glass but I suspect the acrylic will be pretty badly marked.

Will