I did a lot of experimenting tonight. Found out a couple things. I switched out the 1.25 nitro prop with a 1.5" prop on the maxi 1200. I used the flow adjuster casing from a Seio 620 to fit over the prop. Works awesome, or so I thought. I was getting flow close to what a Seio 1500 puts outs. I was only halfway impressed. So, I tired the prop with no guard to see what happened. I couldnt believe it. My 75 gallon tank I was experimenting in turned into a whirlpool. The flow felt easily twice as powerful as my Seio 1500 and spread out in a wider pattern than the 1500. Could the maxi be close to 3000 GPH? Surley not. Im guessing it was easily over 2000 GPH. I was surprised at the wide flow pattern and that it beat the Seio hands down. I wish I owned a Tunze so I could compare that.
Remember, all my GPH estimates are strictly by feel, comparing to Seio pumps.
Anyway, when I put the guard back on, the flow easily got cut in half. I made 3 or 4 crude guards, experimenting with the slot openings and length of the guard. I also put various diameters and lengths of pvc over the bare running prop to see how it effected the flow.
What I came up with is I will need around a 2" diameter pvc in order to not cut down the flow. The 1.5" prop needs quite a bit of space from its blade tips to the wall of the guard. The more room I gave it, the better the flow.
So now I have to try and fit a 2" diameter pvc around the 1.5" prop in order to get the most flow. Im thinking I will start with a PVC test cap when I get one and then adapt that up to a 2" pipe to go over the prop. I cant wait to get it done....