I am rebuilding and extending my office and trying to get my head round how you can add extra capacity to the system ( 1000l) . Display tank is 3x2m with 2.1x0.8m sump. I will have an equipment room 2.1x2.3m and I have lots of space under the new equipment room to house an additional storage tank. I saw Stuarts tank had an extra 600l tank plumbed in for capacity and water changes , and would like to do something similar but dont know how to best plumb it in and not have flooding/siphoning issues!
The extra water change vat on my system is very simple.
Basically, I have a 600lt IBC from Werit UK which stands at the back of the aquarium.
I have boarded the top out to use a work surface except for the hole on the middle to add new salt.
I have a Tee off the main return pump which is hard piped into a port in the top of the container with a shup off valve so that I can adjust the flow in or to shut off altogether. Towards the top of the container I have an out pipe that passes through the side near the top using a standard bulkhead fitting, (50mm).
This simply drains back into the same sump that the water is being fed from so that it does not affect the total flow in the system when I take it offline.
The beauty of the 600lt IBC is that it takes a full bucket of our salt for a refill and so there is no measuring to be done, simple drain through the bottom drain on the IBC, refill, which can take as long as it takes as it is not affecting the aquarium, and then re-salt and bring to temperature. I can then bring the water onto the main tank slowly via the valve.
Simple and really easy to use and operate plus it is fail safe as long as nothing blocks the return from the IBC, which should not be possible really.
Hope this helps