Advise regarding pool pond cleaning

[veggiedog]

For years I kept my in-ground pool dry: about four years ago I let it fill up with rain water. When it had sufficient water level (4 feet or so in the deep end), I added minnows to control mosquitoes (no more mosquitoes!). The pool is now about 6 feet deep (4 feet from full), and it supports a significant amount of wildlife (tadpoles, toads, birds, squirrels, dragonflies, ..., and I now have a bullfrog that is quickly consuming the toads). I have a submerged pump pumping into a 55 gallon drum filled with sand, pebbles, and lava rocks, cascading water into the pool to provide aeration and filtering, but this is not enough for such a large pond.

I would like to clean the pond, but it is full of minnows and tadpoles (countless toadlets too), and I would like to avoid killing those. I am looking for suggestions so that I can add regular cleaning to improve water quality. The pool filter pump still works, but it is a diatomaceous earth filter and I don't like servicing that filter. I have considered converting the pool filter to sand using the original filter housing. I have also considered dropping a sand or pebble filled perforated barrel over the drain in the bottom of the pool to pre-filter water entering the original pool pump filter. I also own a 625-gallon open top plastic tank (8'x2' round) that I can use as a filter housing.

I suspect the pond has considerable muck in the bottom from the continual stream of leaves entering the pool. I intend on purchasing a fine net pool bag skimmer on a pole, transferring muck from the bottom of the pond to the plastic tank to aid in returning some of the inevitably captured fish and tadpoles back to the pond.

I am looking for suggestions regarding the immediate need to clean muck from the pool without killing the inhabitants, as well as suggestions for long term filtering. I would like to avoid purchasing expensive biological filter media, favoring sand (crushed glass?), or lava rocks in the 625-gallon tank. I can cover the tank with a poly tarp (elevated in the center to provide a pitch to keep off accumulating debris). Again, looking for very inexpensive solutions, hopefully leveraging items I already own or are readily available and cheap.

 

[MitchM]

Before you start a major cleanup of your pond, make sure you are aware of your water parameters.
PH, KH, GH, Ammonia, Nitrite, Nitrate, Phosphate and temperature.
There will be a lot of additional bacterial activity and your KH level, for example, will need to be high enough so you don't have a PH crash.
The diatom filter and sand filter medium is of no use to you, it's too fine. You'll need something like Matala pads or poly quilt batting. stuff that you can clean and reuse.
Aggressive water circulation and/or aeration will help stir up the bottom layer of organic matter, BUT, we need to have an idea of about how deep that layer is first. You don't want to get too aggressive stirring up that layer in case there is a buildup of hydrogen sulphide below the layer. Provide your best estimate for how deep the layer is.
It may be best to slowly increase the circulation and keep on top of mechanical filtration for a while.

 

[veggiedog]

Thank you very much for taking the time to provide so much useful information. I will purchase a test kit, tending towards the API master test kit 800 plus the separate phoshate and GH/KH test kits unless you advocate a different set of test kits.

Would it be reasonable to waste the bottom layer of water using the discharge capability of my pool pump? I can lower the water level by sucking off the bottom layer if the hydrogen sulphide stratifies to the lower layers in the pond. Before doing so, I will attempt to quantify the depth of the muck in the deep end: any suggestions on how to accomplish that? Now that most of the tadpoles have transitioned to toadlets, I am hoping that discharging water from the bottom of the pool may avoid killing too many tadpoles/minnows, but I won't attempt that unless it has the potential for helping.

 

[MitchM]

Are you able to see the bottom of the pond at all?
What are the pond dimensions?
Could you post any pictures of the pond in it's present state?
H2S will not stratify, it will quickly dissolve into the main water body and it is just as dangerous to fish as carbon monoxide is to us humans, so you really want to avoid any large releases.

If you do have a pump that you can place on the bottom, it would be best to place it in an area that has very little detritus buildup and pump water up through the filter material that I mentioned before and just have that filtered water return back into the pond. After a while the water will clear up so you can have a better look at the bottom.
Don't start any aggressive water movement until you have the water test results first. Then we can make any adjustments to the water quality, such as adding baking soda to bring up the KH number to a healthy level.

As far as the test kits go, API is what most people here use. It's a good product.

 

[veggiedog]

I cannot see the bottom, only about 1' visibility, very green water. The pool is approximately 55000 gallons when full, but it is a little over 3' from being full now, shallow end only has about 1' of water depth). The current submersible pump is enclosed in a mesh bag that sits at the bottom of the deep end of the pool (over 9' deep when full, about 6' deep now), and that pump is still pumping water into the makeshift bio-filter (55 gallon drum fed from the bottom, discharging at the top, filled with pebbles, than lava rocks, and then poly fill at the top). I will purchase the test kits before I proceed. It is difficult to get a useful photo of the water as I look down into the pool and it mostly reflects the sky (I don't own a polarizing filter). I intend to add poly fill to the original pool pump filter (large stainless steel housing) per your suggestion to aid in future cleanup of the bottom detritus.

 

[MitchM]

If you already have a pump running, then you can start more filtering right away.
Are you cleaning the poly fill on a regular basis now?

 

[MitchM]

The more mechanical filtration you can incorporate into the present water stream, the sooner the water will clear up.
A mixture of coarse and fine filter material would be best.
You'll have to clean it pretty frequently at first, possibly daily.
Once the water clears up, we can look at dealing with whatever is on the bottom.

 

[veggiedog]

No, i am not regularly cleaning the filter, but I have cleaned it in the past. I add pvc pipe to the discharge and route that to my lawn, and then bubble air through the filter by inserting an air wand deep into the filter. I will clean the existing filter, then incorporate the 625 gallon container into the outlet flow to help with additional filtering. I will need to round up more poly batting...

Again, thanks for the useful advice.

 

[MitchM]

If the filters are not cleaned on a regular basis, then the detritus that is trapped in the filter material will break down and actually contribute nitrates to the water which will encourage nuisance algae growth. That's why it's important to stay on top of cleaning the filter material.
With 55,000 gallons, this will take a while.

 

[Angel]

I agree with all above.
If little guy's safety is a concern then filter first.
You could do a small caged pump with a filter ( filter before or after pump) and move as needed and disturb a little bit every day or so to filter out some muck with out messing with the fish to much.

side note lave rocks are a major PIA as the pores clog a lot and need more maintenance then gravel.

one's milage may vary . as a lot of people on here say " one size DOESN't fit all "

 

[veggiedog]

Yes sirs, y'all are of course 100% correct: the filter is horribly filthy (I just checked, and I am currently cleaning it). Filter contents smell horrible, brown, looks like septic tank water. I will discard the poly fill and replace with clean poly fill, and then keep cleaning daily until running clear. I will still order the test kits, and move towards a larger filter. My pool is probably only a 1/4 full now, but even 12000 gallons is a lot for a 55 gallon filter.

 

[Angel]

Yes sirs, y'all are of course 100% correct: the filter is horribly filthy (I just checked, and I am currently cleaning it). Filter contents smell horrible, brown, looks like septic tank water. I will discard the poly fill and replace with clean poly fill, and then keep cleaning daily until running clear. I will still order the test kits, and move towards a larger filter. My pool is probably only a 1/4 full now, but even 12000 gallons is a lot for a 55 gallon filter.

is the end game/goal to fill the pool completely to be a pond? IF this is the case my opinion and mine only is to up your filtering then add the rest of the water.

again my opion the rest on here are more active on both sides of posting and also there experiences .

also as the rest say. PICS?

 

[veggiedog]

I provide these pics so that everyone helping has a better understanding of the problem. Please keep in mind that this pond was not meant to be pretty, I was just fed up with keeping the pool full during the Austin drought that just let up recently. The pool had been much less full until this year when we finally received spring rains, and the original filter appeared to be keeping up as the water was much clearer until this year. Either the detritus finally got to the critical point, or my lack of maintenance on the filter this year was the culprit, but the water had about 3 feet of visibility until this summer. I plan to let the pool fill up on its own via rain water, and I may help it out by directing runoff into the pond as I had done in years past when the rains were lacking. I am a pseudo environmentalist: concerned about waste and excessive consumption, but I drive a fast car, and I drive it fast, so I can't consider myself a true environmentalist. Nonetheless, IMHO there is little justification for large backyard pools in a drought prone location like Austin TX. In spite of appearances, over the last 4 years I have reveled in the significant amount of wildlife that relies on my pool pond for water, and I spend significant time sitting on the edge, drinking cold beer, watching it all happen.

Thanks again for all the help, I think I am on a better path now: I'll keep y'all updated.

Please be kind, and that last picture is a friend of mine, constantly choosing to bathe in my other friend's water bowl instead of his approved bird bath, added for a little levity

In the pic with the poly fill, I had forgotten until removing that I placed the fill in a net bag to facilitate cleaning. It helps keep the poly fill together, but I still managed to pack it into the barrel. I weighed it down with the cinder block in the pic to keep it submerged and still in the water flow path.

 

[veggiedog]

is the end game/goal to fill the pool completely to be a pond? IF this is the case my opinion and mine only is to up your filtering then add the rest of the water.

again my opion the rest on here are more active on both sides of posting and also there experiences .

also as the rest say. PICS?

To support more water in the pool, I would like to convert the blue plastic water tank in the background to a filter, replacing the current filter barrel. I am exploring options for filling the tank with filter media at minimal cost. Alternatively, I am considering creating a bog in the tank. That tank used to be my pond until I allowed the pool to fill, and it worked out great: it had a waterfall, a fountain, and a full collection of toads that called it home. I have two of those tanks, my grandkids use one of them as a play pool, complete with slide.

 

[Meyer Jordan]

If you are planning to eventually have this at a permanent 55,000 gallon level, then it will be necessary to rethink both the overall water flow rate and the filtration, mechanical and biological, on a much larger scale than you are now considering.