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R2R Secret Santa 2020
- Oct 6, 2020
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Yes, the plumbing is 100% the most confusing thing for me. I know everything there is to know about the tank, fish, sump, and all that but the return pump plumbing is so confusing. What about a 1000 GPH hydor?I am in the process of starting a 90-gallon reef tank as well (currently un-drilled but planning to drill). I am new to the marine hobby, but I am an engineer, so I have been planning my own plumbing.
One recommendation that seems common for returns from sumps is to buy a pump with higher capacity than you think you need to make sure you have enough to overcome head height and flow loss through plumbing. Usually, a pump will show a rating based on a head height of zero, which means your selected pump would pump 750 gph if you were just flowing the water right back into the sump. As you raise the height of the outlet above the pump, flow is reduced since it takes more power to lift the water.
I cannot find a flow chart for the Hydor pumps that shows the flow at specific head heights, but it will be lower than the listed gph by the time you lift the water 3-6 feet from the sump up to the display. I would guess the Hydor 750 would actually pump about 300-400 gph if the top of the display tank is about 4 feet above the pump in the sump (purely a guess based on my research).
One reason to buy a bigger pump is that you can reduce the flow up to the display tank until it is the desired flow rate. This can be done either with a control on output (which it looks like the Hydor pumps have) or with a split off the return line that dumps part of the flow back into the sump instead of up to the display and utilizes a gate valve to allow for adjustments in how much is bled off back into the sump. If you can run a pump at lower pressures than it is capable of producing, it will probably lengthen the life of the pump.
Another thing to consider is that it may be helpful to utilize more than one return pump in case one fails. This requires more understanding of plumbing, though, since each pump still needs to be checked for flow rate at head height since they cannot simply add to each other. I am planning to run two return pumps with independent return lines up into my display.
When considering overflows, over-the-top overflows seem like a simple solution to an un-drilled tank. The downside is that they require a siphon to continue. If the siphon is lost (either by the display tank running too low for the overflow until the return catches up or by loss of power on the return pump), you have to re-establish the siphon or the pump may burn itself up running dry or overflow the display. This is why drilling the glass is the better option for overflow control, since it is not dependent on a complete siphon. I plan to drill my tank, but there is a risk of breaking the glass on the tank while drilling. You would need a drill and a glass hole-cutting bit of the right size for your bulkheads as well as an appropriate overflow. Bulk Reef Supply stocks overflows that come with the appropriate glass hole-cutting bit. You need to make sure the overflow can handle the same flow as (or better if much more than) the return system to not restrict the flow and overflow the display tank. There are many videos of how to drill glass. Look it up if interested.
I can explain more about any of this if you have questions, but this may already be an overwhelming text wall, so I will leave it for now.