I suspect this will also be used as a koi Q-tank as well. But since I'm in the mode of trimming my main pond population, the Q-tank usage should be well into the future.
Btw, if anybody in the Sacramento area wants some goldfish then drop me line.
I'll start with the drain being placed. Note the rocks in the back and
on the side. That's called 'soil' around here.
Fast forward to threading the air line for the diffuser dome. A goofy
design but since this is only 1500 gallons I didn't really need the full
4" pipe volume.
Some 3/4" plywood, metal straps, and landscape timbers. Using 3" decking screws through the plywood to the timbers on the outside. Straps at corners and seams.
Multiple screws went in each strap. There are six straps per seam and corner.
Here the frame is nearly complete. Note the sand on the bottom.
I used sheet insulation to pad the walls. So the screws and straps wouldn't
pierce the liner. I also added some 4x4s on top, because the liner was
pre-cut for nearly five feet deep and the plywood is only four feet.
Now I strap the top and place some nice wood around it.
Strapping the top helps avoid the natural tendency for the water to push
the whole thing apart. Also shown are the returns, which were very
easy to put in and I highly recommend these particular 1.5" bulkhead fittings
by Hayward.
When I first filled it, it bulged a little. So I put cemented
a support in the middle on both sides. It still bulges but the supports
make me less worried about it.
And now the filtration. The green thing on the ground is a cheap diaphragm
air pump. The thing in the back is a Sequence 750 (3600SEQ12). The bulkhead
is for a no-niche skimmer and the black thing behind the knife valve handle
is the 3-way valve that allows me to pull more or less water from the skimmer
vs the filter. The filter is an old Cloverleaf II and it seems to be able
to take about 1500gph, depending on water level.
And here it is running. Spraybar and in water returns push the water
from the far end. One day I may put a bead filter on the skimmer return,
just so all the water is filtered on every pass. But so far it doesn't
seem needed.
The cost was somewhat reduced because I got a good deal on the filter and liner. They were second-hand. The liner had never been used, but the project it was orginally bought for fell through. The liner was specially made by the Pearls of Paradise people, so I didn't need to muck with tape or folds.
The filter is made in the UK. But I've heard folks say they can get these for about $500 in California. I don't know where or how.
Other costs:
Plumbing: various 4" ABS ... $100? Plus 2" flex and 2" pipe and bulkheads and fittings and glue ... $300? I haven't added it up. Probably $400-500 for all the plumbing bits and pieces. Those Jandy Never-Lube valves are expensive (about $100 in those alone -- I used two of them, one shown, one to control the water going to the spraybar vs returns). And I used a W.Lim 4" bottom drain in hopes the Cloverleaf would be able to handle 3000gph.
Lumber: I think I spent about $400 for everything. I'm not counting the drill or cut-out tool or saw or various other hardware bits that are useful in other projects.
The pump was retail and I bought some brushes and media bags (AKA sweater bags) for the Cloverleaf.
... I originally estimated about $1200 and I think I spent around $2000 once everything is done. But the redwood on top sure looks nice!