Hi guys. I'm starting a 40g breeder build with 20L sump. And I'm all confused with return pump size, loss of head, what the best plumbing would be and all of the other stuff. I would like a mixed reef, no SPS. I plan on getting a bubble magus NAC 3.5, unless someone thinks there is better around the same price point. And I was looking at the Eheim 1250 for a return. My overflow is 1 1/2". That is all. Any help with return pump size, plumbing or anything you can give would be greatly appreciated. Thanks again.
Long read, but bear with me:
Is your tank drilled for both overflow and return? I see that you have a 1.5 inch overflow hole drilled in the tank, but didn’t see where you mentioned anything about a return hole.
Personally, I prefer to go over the side for return plumbing. This allows more flexibility in terms of how many returns you can run from a single pump and also allows you to tailor your returns to your specific needs. This means you can reduce back pressure on your pump which will allow you to get the most out of your pump.
I do not like to drill holes in my return plumbing. They will eventually get clogged with growth in time and or can be covered by a snail etc at precisely the wrong moment, (IE during a power failure when you absolutely need the siphon break to work in order to prevent a flood). Instead, I prefer to set my return plumbing to a set depth that my sump can absorb without issue.
Using the formula to determine volume of an aquarium, (LxWxH, then divide the answer by 231) I will figure out how many gallons my sump design can handle total, (without flooding) and then design the sump so that its normal operating volume is anywhere between 50-75% of its max capacity. IE if your sump will actually hold 20 gallons, set it up to run normally on anywhere between 10-15 gallons of water.
Then use the volume formula again and determine how deep you can submerge your return before it breaks the surface of the water (in the event of a power failure and back siphon’s), and breaks the siphon. For example, if your 40 breeder is 36Lx18Wx17H, you want to calculate the volume of water that a return will back siphon at 1 or 2 inches…..Instead of 36x18x17, you will calculate 36Lx18Wx1H or 2H. At a depth of 2 inches your sump will need to be able to absorb 5.6 gallons of additional water in the event of a power loss. So, if you set your sump up so that it can absorb an additional 6 gallons, you’re covered.
Hope that makes sense.
With regard to the type of plumbing to use….I personally HATE using flexible tubing for my plumbing. It will almost always kink and if you use clear plastic tubing you will almost always get some sort of algae growth in it which will slow your pump flow and cause you to need to clean it out or replace. This is especially true if you run a refugium or have some sort of light source near the tubing.
Instead, I prefer Sched 40 PVC for my plumbing needs. Dry fit all your pieces before gluing. Draw lines on the plumbing pieces as reference marks for where you need the angles to be when the product is finished, apply your glue, insert the male piece into the female piece at a 45/50 degree angle from where you want the finished product to be, and twist vigorously until the marks line up. This will ensure that the glue is applied evenly and will almost guarantee your plumbing is leak proof at the glue joints. I use A LOT of unions and True Union ball valves. If you even think there is a slight chance you will need to move or separate a piece of plumbing for maintenance, stick a union there. Unions can restrict water flow, so I buy my unions and True Union ball valves, (TUBV’s for short) at least ¼ inch larger than the rest of the plumbing. IE if I have a ¾ inch plumbing and I need unions and TUBV’s for my set up, I will buy them oversized at 1 inch diameter and use a ¾ inch reducer to make them fit my plumbing. This reduces back pressure on the pump which restricts your flow rate.
Hope that all makes sense.