So I have the Red Sea reefer peninsula 650 plumbed to a 7.0 Pump. According to the flow chart below, I am running at 13ft of head pressure at 550gph. I’m using the Neptune 1” flow sensor to give me my numbers and I tested with two different flow sensors to make sure the sensor was working properly. I’m trying to run the Triton method and need about 1000 gph flow. So I bought the Sicce 9.0 Pump from bulk reef supply and installed that pump. Now I’m getting 670gph. But according to the flow chart, at the same 13ft, I should be getting around 1500gph. Something does not make sense, has anyone else had issues like this?

Interesting I have the 7 on a 55 I just guessing that I am getting 1000, but not sure but I only have 1 90 in the return line from the pump . I have mine wide open, but I do not have a flow meter on this one, I will have on my new build

The one inch flow flow sensor is also a restriction. When I went to a 2 inch flow sensor I gained 100gph. The biggest difference though was removing 1 (unnecessary) elbow and moving from 1 inch pipe to 1 and 1/4 inch pipe. I also upgraded the returns to 2 - 3/4 inch locline returns and 1 - 1/2 inch locline return. This brought the output of my reef octopus return pump from about 500 to around 1200gph

My return is 1” and I would think that the head pressure wouldn’t change from the 7.0 to the 9.0, I should just be able to follow the line over on the graph and have my exact gph with the 9.0 correct? Or is that not how it works.

Well. What I am suggesting is that if you have a discharge with 2 - 1/2 inch locline returns then you don’t have a 1 inch return. Area of two half inch pipes is .4 inches squared while the area of a 1 inch pipe is .79 inches squared (double the two half inch pipes combined). That was a mistake I made. So, I just wanted to have you look at the area of your tank return. There is only so much these little pumps will do through a tiny pipe.

Are you sure they are 1 inch and not3/4 inch lock lines I thought that was the biggest they made, but I might be wrong

You’re right, I have this https://vividcreativeaquatics.com/s...ate-xxl-return-line-upgrade-25mm-to-34in-rfg/ It’s a 25mm Red Sea outlet adapter to two 3/4” random flow generators

I’m not sure, but it shouldn’t matter since I was getting 550 with the 7.0 and only 670 with the 9.0 with no changes in plumbing. I’m not an expert in flow dynamics but it should definitely be a way larger difference between the two pumps with the same head pressure.

Well any time you make a bend in your plumbing or a reduction in the size it will reduce your flow by a lot. I will be installing 3 flow meters at least on my new build can't wait to see what they tell me

Sicce e-mailed back and said it is within spec and they tested it on their end with the same results. The best part is Bulk Reef Supply won’t return it because it’s been used. So I spent almost $400 for a 120 gph difference, that’s great.

The head loss consists of the elevation difference between the water level in the sump and the tank plus the frictional losses in the piping. The elevation difference remains the same, but the frictional head loss in a given piping network increases by the ratio of the square of the flow rate. I don't know your exact arrangement put assuming you have about 4 ft of elevation difference between the level in the sump and the level in the tank, that means that you have 13 minus 4 or 9 ft of frictional losses at 550 gph. When you increased the flow to 670 gph with the new pump, the frictional loss became (670/550) squared greater or almost 50% more (13.5 ft instead of 9). The elevation difference remains the same at 4 ft so now the total head requirement is 4 + 13.5 or 17.5 ft, which is reasonably close to the 9.0 pump head curve. To get to 1000 gph with your existing piping, you would need 9 time (1000/550) squared plus 4 ft or almost 34 ft of head pressure at 1000 gph. The problem is your piping is too small for 1000 gph. You need to increase the size of your return piping to at least 1-1/4" and add another identical 1" return parallel to your current one you have to get 1000 gph. I would also upsize the meter with the piping or add a separate one for each 1" return.