Return pump question

[wa1tx]

I set my 125 up for 5-6 turns an hour using an Eheim 1262. I am starting to question that low number of turns per hour. I have seen a lot of 125s' using Mag18 pumps. Anyone have any advice or suggestions on this topic?

[Timfish]

There's no right answer, it's what you think looks best. 10 X tank volume is usually touted as the minimum acceptable I have tanks with far less than that through the sump and this tank:is one I maintain that barely has that internally with 2 Korrallia 2s and two Aquaclear 70s.

Now if you want to evaluate your tank to see if you are getting a build up of CO2 you can check it by monitoring your pH. Since CO2 combines with calcium carbonate to form carbolic acid it will lower your pH. This process is why your pH is usually lower in the mornings before the lights turn on since algae and the rest of the animals have been making CO2 all night long than in the evenings before the lights turn off when algae has been removing it all day. You can do this two ways. One is to measure the pH at a given time to get a benchmark (pH can change throughout the day), add an air line or pump that gives you vigorous surface agitation for 24 hours then test again at the same time of day as the first test. If the 2nd reading is significantly higher you need to do something to increase the gas exchange. The second way which is probably better since it eliminates the possibility of a high CO2 level in your house influencing the readings is to syphon off 5 gallons from the middle of the water column and set it outside aerate it vigorously for 24 hours and then compare the pH to the pH of the tank it was removed from. Again if there is a noticable difference you need to look at improving the gas exchange.