After having new pool and sand filter installed by pool store two years ago, they recommended changing sand after two years. Purchased new sand and went to remove old. Sand in filter is as har as a rock -- literally chipping it out in mostly hand sized chunks. What caused this and what can we do in the future to prevent this? Old pool with sand filter for years and years and always just poured old sand out with no problems.
Filter sand hard as a rock!
- Thread starter tablpa
- Start date
![20180519_164023[1].jpg](/data/attachments/63/63590-e3a1551cbeae2cafc42835cbb3642a1c.jpg)
What have you added to the pool besides chlorine or muriatic acid?
Any use of flocculants, clarifiers, or other pool ‘potions’?
While your surly needs changing, the previous stuff that just poured out did not need a change. Pool sand does not wear out. As Dom alluded to, many pool store potions will contaminate it and cause it to gum up, kind of like yours is.
The only thing we have ever used with this filter is stabilizer/conditioner at the beginning of season, and chlorine and muriatic acid during season. Filter and sand was new in June 2016 and installed by pool company. We know we have hard water from our well water, but have had the same well for 40 years and had pools for 30 of those. Prior to this new filter in 2016, never had this issue and used baquacil for probably 20 of those 30 years before converting to bleach. Replaced our sand every 2-3 years during that time as was suggested by local pool store. Finally got the rock hard sand out of the filter, but just don't want this to happen again. But since we don't know what caused it, don't know how to prevent it.
What was this ‘stabilizer/conditioner’? Was it pure CYA?
What form of chlorine are you using? Have you been using any Clorox bleach with ‘Cloro-max technology’?
Proper pool filter sand should never get hard like that from just sodium hypochlorite, muriatic acid, and CYA.
Are you certain the proper sand was added to the filter to begin with?
Calcified sand...?
Another person had a similar issue last year by the looks of it:
Calcified Filter Sand
Another person had a similar issue last year by the looks of it:
Calcified Filter Sand
Again, proper pool filter sand should not do this at all.
Usually this is the result of using clarifiers and flocculants.
Something is binding the sand together, and it’s not sodium hypochlorite, muriatic acid, CYA, or baking soda.
I believe Costas has the clue. For one reason or another calcium has solidified your sand. Can you post test results and tell us your Calcium level, pH and TA. If they are not badly out of guidelines, I'll bet they have been in the past......for long periods of time, too.
The solution is to get your filter cleaned up however you can and then start a regimen of pool water testing which will prevent that condition from returning.
The solution is to get your filter cleaned up however you can and then start a regimen of pool water testing which will prevent that condition from returning.
sktn77a
Gold Supporter
Why not take a sample back to the pool store and tell them "this is what you sold me 2 years ago, what's the deal?" Maybe they had other customers with the same problem.
This ^^
(though OP did mention the pool store advises to change filter sand every 2-3yrs)
In response to a couple of questions -- don't think used any Clorox brand bleach, mostly Walmart brand. Don't have testing results from this year yet, as do not have pump/filter hooked up and pool opened. Was just getting ready and going to change sand in the filter when we found this. Also don't know the brand of sand used as pool company set it up as a new install two years ago. Our original Hayward filter was a DE filter for 10-15 years, then went to a Hayward sand filter for the next 10-15. With new pool install 2 years ago we were given the Aquaview sand filter.
And yes, we know we have hard well water which is what we use to fill the pool. We have always been very good about keeping pH and chlorine levels in check, but the hardness is always quite high. Never noticed any problems this caused in the past, we have crystal clear water and no issues with sand hardening in the past.
If it has been caused by the hardness, any idea why just happening now. And is there a good way to decrease hardness without dropping the pH?
And yes, we know we have hard well water which is what we use to fill the pool. We have always been very good about keeping pH and chlorine levels in check, but the hardness is always quite high. Never noticed any problems this caused in the past, we have crystal clear water and no issues with sand hardening in the past.
If it has been caused by the hardness, any idea why just happening now. And is there a good way to decrease hardness without dropping the pH?
Do you have any left you could drop in a cup of vinegar?
We've used the Washing Soda method with our TINY vinyl pool
BBC - GCSE Bitesize Science - Hardness of water : Revision, Page 2
- May 3, 2014
- 59,332
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
The only way to remove calcium from your pool water is by exchanging the water with fresh water that has less calcium or by using Reverse Osmosis.
Good luck.
Good luck.