Trying to "deep clean" very dirty sand

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seven7seven

0
Nov 17, 2018
10
South Africa
Hi All,

I'm busy SLAMing my pool (first time).

I'm on day 5 and the green is all gone but the water is still very cloudy so I started reading more here about filtering and came across the "sand filter deep clean" post yesterday and tried to follow it, but have encountered two issues:

1) My sand is VERY dirty:
- I have pulled out around 20 clumps of mostly dead plant matter, some bigger than others, but there seems to still be many more in the sand, particularly around the sides of the filter:
20181117_164133.jpg
- There are little bits plant matter all throughout the sand that the "deep clean" doesn't seem to remove very much of:
20181117_163643.jpg

I removed about 2 gal of sand and put it into a bucket (see point 2 below for reason) and used the hose in the bucket to try deep clean it. After about 5 minutes the water eventually started clearing, but there are still loads of plant bits throughout the sand (as seen in pic) - they're not light enough to float to the surface so just stay stuck in the sand.

It seems to me that I need to actually just replace the sand?

Further, how do I prevent this in future? The sand was replaced 3 years ago (before I knew about TFP & deep cleaning) and I've backwashed it regularly (+- every week in summer & every 2 or so in winter) by backwashing till clear, then doing rinse cycle. Only this week did I learn about doing the second backwash & rinse cycles - could that be the key?

2) I couldn't get the hose all the way to the bottom of the filter. My filter is deep and the hose just can't push the sand out the way deep enough.

I then attached the hose to a length of PVC conduit and tried with that but could only get all the way to the bottom in a couple of spots.

Today I removed about a 3rd of the sand (using a wet/dry vacuum) into buckets and then tried again but still no luck getting hose to bottom of filter.

What am I doing wrong?

Thank you in advance for the help :)
 
Are those cluumps as solid as they look? What kind of vacuum do you use? What kind of stuff falls into your pool?

The answers to the above questions will help us figure out how to keep this from happening again.

Now to what to do now. What do y have more of? Time or money? If money then new sand. If time put the sand in a large wheel barrow a little at a time. Clean it then it back in the filter.

Kim :kim:
 
Anytime you have a heavy debris load in the pool, vacuum to waste and then backwash, rinse, and top off the water level in the pool if needed. It looks like you may have been vacuuming heavy debris loads to filter and not backwashing long enough. Have you used any flock since you last changed the sand? Improper use of flock can cause sand issues too.

The sand should be loose enough that you can gently work the hose through the sand to the bottom of the filter. You might be hitting laterals before you get to the bottom of the filter, so be careful when you are doing your deep clean. If the sand itself is not loose and holds clumps I would go ahead and change it.
 
kimkats said:
Are those cluumps as solid as they look? What kind of vacuum do you use? What kind of stuff falls into your pool?

The answers to the above questions will help us figure out how to keep this from happening again.

Now to what to do now. What do y have more of? Time or money? If money then new sand. If time put the sand in a large wheel barrow a little at a time. Clean it then it back in the filter.
Click to expand...

[COLOR=#3E3E3E said:
zea3][/COLOR]
Anytime you have a heavy debris load in the pool, vacuum to waste and then backwash, rinse, and top off the water level in the pool if needed. It looks like you may have been vacuuming heavy debris loads to filter and not backwashing long enough. Have you used any flock since you last changed the sand? Improper use of flock can cause sand issues too.
Click to expand...

Hi Kim & zea3,

Thanks for the help - I'm going to go ahead and have the sand changed.

In terms of prevention/causes:

Clumps: they are soft enough to easily pry apart with your fingers (I'd done so for the two in the photo, to show what's inside them), but firm enough to pull out of the sand (even if buried) without them breaking up.

Vacuum/cleaner: was a Zodiac G2 up until a few months ago when I replaced it with a Voyager which is a basic flapper suction cleaner which is meant to be very realiable (I got tired of often replacing parts on the G2).

Stuff falling in: quite varied depending on time of year but mostly includes:
- palm tree leaves (the long thin ones but neither cleaner is able to suck much of these up so I have to remove via net)
- small (about size of my thumb) up to large-ish (about 2/3rds size of palm of hand) leaves
- palm tree little 'flowers' (don't know what to call them) and other small (about jelly bean size) blossoms
- up to 2 months ago (had to cut tree down), conifer tree leaves which are small 'needle' like leaves

Floc: yes I used it a handful of times but vacuumed to waste.

I leave the Voyager (and did same with G2) in the pool permanently (but not now when SLAMing), continually sucking up the debris so that I don't have to manually - sounds like doing this plus not backwashing long enough is likely blame?

Also since starting to do the 2nd backwash cycle, I see that some of the dead plant matter (the black bits) are coming out in the 2nd backwash cycle (which I wasn't doing before) which I don't notice in the 1st cycle.
 
Try using skimmer socks in the pump baskets. I have a total of 6 skimmer baskets, all ready to go with socks. When the baskets fill up, with the filter running, you can pull up one basket and quickly replace with another basket. This way, the matter and debris in the basket will not float during the removal process. Keeps a lot of junk from running back to the pump and into the sand filter. A small rock without sharp edges inside the basket is used on my end to keep the basket down when the filter shuts off. Never once have I had to use Floc either as water remains crystal clear.

The only other item that you may want to try is a DE alternative that coats the sand for better filtration. When you backwash, the DE alternative (like Fiber Clear) is on the bottom of the matter (I would think so), and then everything would come out of the backwash hose. If you are to use the DE powder, watch the pressure quickly. I had little pressure increase after the addition. Just some thoughts.
 
Okay so lets do a one, two punch.

1. Replace sand
2. get skimmer socks- VersaPro 210 21 Scientific I know you are in Africa so you might have to so some extra searching to find something like this.

The idea of the skimmer sock is to keep the big stuff from getting to your filter and causing this kind of problem.

NOW lets talk about how to keep your pool from needing to be floced.

1. get a good test kit. Try here: Total Pool Water Testing Kit, Salt Water Clear Choice Labs (I do see they are out of stock but you can at least find out if they will ship to you). If you can't get that one then look for Taylor 2006C (the number 6 and letter C are very important due to this kit having more of the regents so you will not have to order replacements as often).

2. Reading this to get a quick snap shoot of how we do things here at TFP: TFPC for Beginners

3. Reading this for more in depth learning: Trouble Free Pool School

4. Asking LOTS of questions!

I will ask you a question about your pool care now to get an idea on how to get your started. How do you add FC (Free chlorine) now? Tablets? Powder? Liquid chlorine?

Kim:kim:
 
As you are doing, change your sand......you are hopelessly clogged up within your filter.

Once you have clean, new sand, stop doing what you are doing and take a new approach to your filter maintenance.

1. Don't use floc......I believe that contributed to your problem.

2. Backwash when your pressure reaches 25% greater than when it was clean.....do you have a working pressure guage?

3. Extend your backwash time by 50% over what you were doing......it obviously didn't get your filter clean.

4. As someone above mentioned, use skimmer socks to minimize the debris going into you filter

As an aside, I think this is the first time in 12 years I have suggested changing the sand........your filter is just too plugged up (probably from adding floc) to ever get it really clean and filtering properly.
 
Cat and Dave, one of my first thoughts also was skimmer socks; however, the pool vac he is using precludes their use in the skimmer. Since use of a sock in the pump basket is not recommended any time, the only way a sock might be used in his situation is to modify the Voyager installation somewhat. Instead of installing the flow adapter in the bottom of the skimmer, try installing it in the hose line outside the skimmer and use a skimmer top like is used for manual vacuuming. not sure if it would work but might be worth trying. or get a robotic cleaner.
 
the pool vac he is using precludes their use in the skimmer
Click to expand...

Can you please explain? A little confused. If there is a skimmer, it creates suction. There should be a basket and a vac plate, that allows the pool owner to vacuum, with out without socks. I vacuum with socks to pick up the fine dirt, but use the expensive socks, not the hair net type as they do last longer and do not mind spending the extra few dollars. Only time I have to vacuum without the socks is under heavy leaf cleanup, but this year I knocked the tree down (no more problems and stress). These are great a trapping finer type of dirt. They will last around 2 months unless you have high chlorine levels.

Amazon.com : U.S. Pool Supply Pool Skimmer Filter Socks, Pack of 36 - Ultra Fine Mesh Filter Sock Net for Skimmer Baskets - Skim Remove Leaves, Bugs, Oil, Pollen, Algae and Other Floating Debris : Garden Outdoor
 

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Additionally, you may want to look into an inline leaf canister for your suction cleaner - something like a Hayward W530. This would trap the debris prior to entering the skimmer, pump basket and filter.
 
Hi everyone,

Thanks so much for all the responses!

I've been phoning around to get quotes on having the sand changed and discovered that for some reason the standard pool sand grain size here in South Africa is much larger than what I've read on TFP (and elsewhere on the web) is the standard. Ours is "0.6mm - 1.5mm" (and this seems standard across brands here) whereas I read that 20# is much much smaller (0.45 - 0.55).

I asked two of the pool companies about it and one didn't know what they were talking about and the other said they might be able to get finer sand, which is the "old sand we used to use" but cautioned that I would have to backwash more frequently as it will clog up quicker.

What are yours thoughts on this?

@kimkats:
Thanks so much
- I really struggled a few weeks back to find somewhere that would ship a decent test kit here, tried a whole bunch of package forwarders to see if I could order off tftestkits.net but no luck - as a last resort I found a Taylor 2006C on Amazon via third party seller which is now its way here ($183 later - the kit alone was $140 which is crazy high but they were the only seller that would ship here). I do currently have the 'Taylor Replacement Reagent FAS-DPD Refill Kit (Large) - Over 100 Tests' and a SpeedStir which I ordered at same time but it shipped much faster, thankfully, so I've been using that for the SLAM.

- Chlorine: Since moving in (4 years ago), I've been using a mix of stabilised & non-stablised (we get a brand here called Kleenklor which has cal-hypo pucks in it wrapped in plastic to slow down the dissolution) and then adding granular cal-hypo 60% (HTH) weekly.

For the SLAM I've been using the granular cal hypo. The stuff they sell here doesn't dissolve nicely though - if I sprinkle it around edges of pool in evening and brush a bit, even in the morning there'll still be some granules on the floor of the pool.

I see bleach is recommended on TFP but our store bought bleach is very weak 4% making it a no go price wise - busy trying to find a supplier of stronger bleach to see if I can use that instead. Found a place that I could get 12% from but it was going to be $60 for 25 liters (6.6 gal) compared to 8kg of the 60% cal hypo for $20.

@duraleigh:

Thanks - I will avoid FLOC in future, now that I have awesome TFP knowledge :D
I'll look for some skimmer socks & increase backwash time (& do the 2nd backwash cycle).
I don't have a pressure gauge. They're uncommon here - I've never seen a pool with one installed. But my pool does have a little island with a return jet right on the top facing the sky, which makes a little vertical fountain, which I have been using as my 'pressure gauge' as I can see when the height of the water it's pushing out is getting lower.
 
Get a pressure gauge. I don't know what the fountain is but I don't see how you can successfully manage your pool not knowing the psi. You NEED a pressure gauge, regardless of how uncommon they are.
 
Just a note: No matter what type of powdered chlorine you use, you are adding stuff your pool that doesn't go away on its' own. Cal -hypo adds calcium and standard pucks add CYA To effectively SLAM you are going to have to get some form of liquid chlorine. The amount of chlorine that is needed for a SLAM will quickly build up the 'additives' to an unmanageable level. You may have to consider the cost of water, versus the cost of liquid chlorine.
 
duraleigh said:
Get a pressure gauge. I don't know what the fountain is but I don't see how you can successfully manage your pool not knowing the psi. You NEED a pressure gauge, regardless of how uncommon they are.
Click to expand...

Thanks Dave, I'll look into it.

Anyone care to advise/share their thoughts on the sand grain size issue, please? I haven't changed the sand yet - thought it's best to get input on the grain size first.

Repeated here for ease of reference:
I've been phoning around to get quotes on having the sand changed and discovered that for some reason the standard pool sand grain size here in South Africa is much larger than what I've read on TFP (and elsewhere on the web) is the standard. Ours is "0.6mm - 1.5mm" (and this seems standard across brands here) whereas I read that 20# is much much smaller (0.45 - 0.55).

I asked two of the pool companies about it and one didn't know what they were talking about and the other said they might be able to get finer sand, which is the "old sand we used to use" but cautioned that I would have to backwash more frequently as it will clog up quicker.

What are yours thoughts on this?
Click to expand...

Thanks!
 
You may find that small debris slips through the filter with larger sand grains. The smaller grains of sand clog more quickly because they catch more debris. If you use the standard size the locals use you may find small debris coming out of the return when you vacuum, or that you have to vacuum to waste to remove them from the pool. Look up the owner's manual for your filter and if it recommends the finer sand then you need to try to find that sand. Don't use any floc and backwash/rinse as needed and the sand should be good for many years.
 

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