Converting my pool to a pond (sort of) - need advice on filter

[Nemoralis]

I'm putting a few fish in my 15,000 gallon swimming pool. Getting rid of the old pool pump and canister filter (and chlorine) and replacing with a homemade skippy-ish filter. However I have a few questions.

First - my fish load. It will be almost nothing. I want one or two 2-3' Florida gar and then a couple smaller fish to take care of mosquito larvae. So maybe 100" of fish in 15,000 gallons of water. Also no plants, muck, debris, substrate, etc in the actual pool. I'll put some fake stuff in for cover for the fish but otherwise I want a clear, blue pool like I have now. (I will be installing a UV sterilizer in addition to the filter).

My original plan for the filter from the bottom up (already purchased these things):

- Plan to have intake coming through the wall of the stock tank, not "skippy style" in from the top
- Plumbing for a swirler and drain
- Lighting grate
- Two matala mats to cover the light grate as a pre-filter
- Bird netting to make bags for bio filter material
- 1/2" poly strapping for bio filter
- Another light grate to go on top of the strapping material
- Another matala mat on top of that grate
- A small layer of gravel on top of this mat, so I can plant some plants and make it visually appealing

I already have a 100 gallon stock tank, but I know this is way too small. I'm thinking of buying another, larger one for the skippy filter and turning the 100 gallon into a gravel bog filter, and using both. Thoughts on this?

I bought a 9000 GPH pump, which I'm realizing may be too big for my stock tank(s). My options are to exchange it for the 6600 GPH model or???? I guess divert water but seems like a waste of electricity as 9000 GPH model is twice the monthly cost of the 6600. Thoughts?

I was hoping that I could use my pool's original plumbing. It uses 2" pipes. Was just going to pop the old pump off the pipes and put in my new pump, and put my stock tank(s) in place of the cartridge filter. The problem is that the original plumbing uses 2" for the intake and outtake, but for a skippy you need larger outtakes than intakes, right? Would I be able to put in multiple 2" outtakes on my filter and have them join with one another before entering into the original 2" pipe and go underground? Or this would just cause it to back up into the skippy?

Not sure what to do here because I really don't want to dig up my yard - want to use the original plumbing because it's there and functional and already buried (and it's a perfect location for the filter and pump - out of sight around the side of the house).

I know I've probably made about 474838252847 mistakes here. If someone would be kind enough to point them out - I'd be forever grateful!

 

[Meyer Jordan]

A couple of quick observations-

-you will not have a "clear blue " pond. Clear..yes. Blue...no. All submerged surfaces will quickly be covered with algae, which you need.

-An open gravity-fed filter will not work with the existing plumbing. Primary reason is the outflow plumbing needs to be at least twice the size of the intake plumbing at all points, unless the pump is placed on the outflow line. Swimming pool plumbing is designed for use of a pressurized filter. This is what I would recommend staying with.

 

[Nemoralis]

Gotcha, makes sense. Could I use the existing 2" piping from the pool to the filter and then use new, larger piping from the filter to the pool? Would at least half the amount of new pipe I have to run.

Or do you think it would be better to build a pressurized filter for my pool? Any links to a DIY pressurized filter build?

Re: algae covering the pool surfaces. I'm not sure about that, I worked at an aquarium as a diver in college and we kept the aquariums clear and free of algal growth on all surfaces by wiping them with a sponge brush pretty regularly. On the outdoor aquarium (in sun) we had to do it twice per week. But that was a huge aquarium, much bigger than my pool. I think I can keep surface algae in check although it might be some work, and it's work that I'm used to. My main concern is the algae in the water column.

 

[sissy]

Thing is algae on the sides is good for the health of the fish .Peroxide helps with some algae but on my waterfall I let it grow because i helps clean the water and plants in my filter really help keep everything clean .Plus I have 2 filters

 

[Nemoralis]

I plan on putting some large fake plants (trees) in there and I'll let algae grow all over them (I think it makes them look more natural anyway). I just want the walls of the pool kept clean. I know some algae will grow, I'm not too concerned about a few patches. Just want it mostly blue.

I've actually been pretty shocked, the pool has been chlorine free for about 4 weeks now, in full south Florida sun, and is only just now getting a few faint brown patches. I have some large pterigoplichthys in there now, we'll see if they help at all.

 

[Patfish]

Well?
How did it turn out?
Pictures?