Pond filter rebuild #3 bazillion

[Sploke]

Alright I think I finally have this thing to an iteration that I will actually like long-term. Its not quite done yet, gotta run to HD to get a few more fittings to finish it up, but its close. There were a few features I wanted to integrate to make things a bit easier:

1. I wanted to move the pump down to the floor. Having it high up on the shelf made it practically impossible to prime.

2. I wanted valves on each leg of the filter to close each one down independently.

3. I wanted a backflush loop to clean it out periodically...ties in with #2.

4. I wanted an easy way to prime it with a hose.

So, this iteration accomplishes all those things. First off, I built the bottom manifold. This one has four male threads for each leg of the filter to screw onto. This way if I ever need to, I can take them off individually without having to cut anything. I'm tired of cutting things apart and having to rebuild them because I glued absolutely everything together. You can also see the hose pigtail with a garden hose fitting on it for priming the system. All I need to do is attach the garden hose, open the ball valve, and it will purge all the air from the bottom up.



Here are the legs of the filter. Each one is 4" PVC filled with lava rock. 1" FPT on one end, 1" male hose barb on the other.


Here they are attached to the bottom manifold


Here is the network with the pump attached. The clear line comes in from the pond, into the pump, and out. Straight out of the pump goes into the filter. If I close that ball valve and open the other one, that sends water up into the top of the filter and down through (essentially backwards from normal operation). There is a hose pigtail on the bottom, so if I open that ball valve, I can backflush the system. Additionally, now that I have individual ball valves on each leg, I can backflush them one at a time, getting a lot more flow through each one, hopefully doing a better job.


The clear line here not attached to anything is the backflush line. That will be attached to the T right there, which needs a ball valve after it. That way I can close it so it will actually backflush instead of just bypassing the filter and going back to the pond. You can also see the ball valves on each filter leg, right before going into the exit manifold. I used hose barbs rather than threaded fittings here just to make it easier to take it apart if I need to.

Here you can see the in/out through the basement wall. The holes used to be for the oil tank fill pipes, but they were relocated. The one hooked up is the supply, the other one obviously needs to be cut, and will be the return to the waterfall.

 

[Rbishop]

Looking good!

 

[ohbly]

great work!
what grade lava rock did you use?

 

[Reddog80p]

Nice big toe sploke!! Btw the filter system is looking alot more user freindly :grinyes:

 

[Sploke]

It comes in grades? I dunno whatever they sell for gas grill use at home depot.

 

[hankn]

How large a pond are you filtering with that setup?
And I thought the 65L gravitational filter I am building was a big job.
Hah. You got me beat

 

[Sploke]

its about 1500gal.

 

[Reefscape]

Great work so far Matt.....

 

[Sploke]

I realized that I never updated this thread after getting the filter completed. I had turned it off for the winter, its been warming up and the water is turning green again so I decided it was about time to fire it up and turn the UV on again. This was also the first time I've gotten to try the backflush loop, which seems to have been very effective. So, here are some pictures of the completed setup, and how the backflush works.

Here are the two prefilter boxes I use. I had to silicone ceramic tiles to the bottoms of them, otherwise they would float when the sponges got gunked up and the pump would start sucking air.

And in the water

This is the completed setup - water comes in, through the pump, up through the filter legs, through the UV and back out.

Here is the pump and the ball valves used for flushing. The valves are marked NO (normally open) and NC (normally closed) for hwo they run during normal filter operation. The output of the pump goes into the bottom manifold, then up through the filter legs.

Here is the top manifold. The four smaller valves are open, the larger one is closed to keep it sealed up for the winter. This also stays closed to backflush.

Here are the valves the other way. By switching them, the water is diverted past the filter legs, then back down so the water flushes through in the reverse direction that it goes during normal filter operation.

Now, closing all the top manifold valves but one, I can force all the flow through each leg of the filter individually to flush out any mulm thats settled in the bottom.

The bottom manifold has a small pigtail coming off - by attaching a hose and opening that valve, the backflush water gets washed out the bottom into the hose...

...and down the footing drain in my basement floor (this is also where I drain water during weekly water changes).

Now, the valves during normal operation. The bottom valves have been reversed so water is now flowing upward through the filter legs, out the top, and straight through to the UV filter.

Hose disconnected and valves back to normal

And this is where it comes out.

I fished the watercress out of the pond to put it back into the waterfall - makes a decent veggie filter and helps to hide the plastic. IT overwintered fine on the bottom of the pond - its looking a little limp from being submerged, but it should perk right up.