Hello, New to fish keeping. I have a 30 gallon tank with a Superfish Aquaflow 300 internal filter. I’m not sure what the best position is and whether or not to use the optional spray bar that comes with it. The spray bar seems to reduce the noise but I’ve read it can put unnecessary pressure on the pump - is that true? If I use it, is there a right or wrong way of directing the flow of water? Does there need to be bubbles on the surface? Also, should I turn it up full or not? I have two Jack Dempseys and two Firemouths and I read their natural habitat is slow moving water - does that mean I should turn the filter down?
Spray bars don't cause pressure on the pump so it's fine to use. Position it how you like, just let it disturb the water surface.
Just another point, but the tank is too small for those fish. A pair of Jack Dempseys need a tank at least 4ft long by 18 inches wide; if you have two males you'll need more space than that. To keep JDs with other cichlids like the firemouths you're looking at a 6 foot by 2 foot to maintain the peace when they all mature.
Re the jack Dempseys, I’m not sure what to do now that I have them; before choosing what fish to keep I read conflicting advice on the Internet about what would work therefore decided to take the advice from my local fish shop where I bought the tank, I was guided by them who told me these would be ok for my tank ☹️ In fact I’d hoped it would big enough for 3/4 cichlids and was surprised when they said I could put 6/9 in there. They said to stick with 4 first for a week or so to let the filter build up then I could get some more. My original plan was to have 3/4 cichlids, an algae eater and perhaps a few mollys.
Unfortunately, the shop has given you very poor advice. I would be looking to either upgrade the tank or rehome at least one of the JDs. Even one with firemouths may be a problem as in that size of tank a mature JD will see all of it as his territory.