Sand filter replace or fix

[Sim]

I have 25 year old in ground pool (~30k gallons). Current filter is sta-rite (30 inch model with 400lbs of sand) has been in place for these 25 years. I bought the house 4 years ago and the last owner told me he replaced the sand in 2007 (he could not generate a receipt or any paper work thou).

Pool was closed for all of winters (Seattle) as a pipe burst. Pipe was fixed in May of this year but the water is not clearing up all (I even emptied the pool and refilled it with fresh water (70% water was replaced) but it will just not clear up0. My pool guy changed the 'O' rings in the old brass valve but that did not help either. It is now coming down to the filter itself.

Please help me with following:
Fix things:
- Replace sand in sand filter (~ $800/)
- Change valve to new multiport ( ~ $600/)

Replace things (needs new plumbing around the motor):
- Change every thing and replace with a new commercial quality sand filter with 600lbs of sand (~ $2500/)
- Change everything but replace with a smaller sand filter with 300lbs of sand (~ $1600)

Also, could there be anything else wrong with the pool system. changing all of this will clear up the pool for sure?

Pool is in very inaccessible area under the stairs (inside garage) as such labor involved is higher, + this is Seattle so you may more for everything here

 

[mknauss]

Welcome to the forum.

Do you have test results? Are you sure you do not have algae that is causing the cloudy water?

Typically sand does not wear out. It is over a million years old and a few years in a sand filter will not harm it. Now, if a bunch of pool store potions have gunked it up, that is another matter. Have you deep cleaned the sand?

Also -- can you add a signature? Pool School - Read This BEFORE You Post

I get the impression this is an indoor pool, but a signature and your the city/town/state/country the pool is in can help.

Take care

 

[Sim]

Thank you, I just updated the signature as well.
- I test the water using Taylor kit, and all numbers looked good (Chlorine, FC, Ph, CYA, Alkanity)
- Never cleaned the sand (not in 10 years atleast)
- Pool is outdoors (Seattle) and next to bunch of trees, which drop lot of leaves and other things through out the year (before these issues appeared this year the pool was always crystal clear with regular chemical regimen)

Here's an interesting thing about that is happening with the pool.
- After shocking the pool and letting it run for few days, the water will get little clear and the gunk will settle on the bottom. When I vacuum the pool, I see the gunk coming right back into pool through the inlets and the water will get all cloud and dirty again. This was not the case in the past. (I have an old brass valve which has only two options - regular operation and backwash. When i vacuum the pool , the valve is set to normal operation, i.e. the water goes through the sand filter and comes right back in through the inlets)


I incorrectly mentioned in my original post that pool is inaccessible. Actually the pool is fine but the pool equipment is inaccessible (Especially the sand filter)

 

[mknauss]

Any chance you would post your actual test results? This sounds like algae to me. And sand filters have issues in clearing the dead carcasses.

Have you ever SLAM Process or Overnight Chlorine Loss Test? I would think a Overnight Chlorine Loss Test would be instructive.

Take care

 

[Sim]

I will get the latest numbers tonight.
Meanwhile, my question is also: why would dirty water come back as it to the pool (through inlets) even thou it is going through the sand filter. As I mentioned above, I changed almost all of the water and vacuumed other debris out from the pool using a rented trash pump and i never expected it (water) to go bad within a week of water replacement. Is there another component to the pool that i could be overlooking other than the filter and valve

 

[mknauss]

As you had and still have cloudy water, it is most likely a chemical issue, not a filtering issue. You have algae. Now, the filter needs to filter out the dead algae, and sand filters can have issues doing that quickly. Once you determine if you have algae by performing the two processes I stated above, then you can focus on clearing the cloudy by adding DE to your sand filter Pool School - Add DE to a Sand Filter

A slightly dirty sand filter filters better than a clean sand filter. That is what the DE does, makes it dirty.

Good luck.

 

[zea3]

If the filter is not catching the debris you vacuumed, it could be that the sand has channeled and is allowing dirt to return to the pool. To correct this problem you would need to deep clean the sand, which removes debris and re-seats the sand bed. The instructions for deep cleaning a sand filter are listed here: Deep Cleaning a Sand Filter

 

[Sim]

Hello again, took a break while I got the system upgraded. Got a new Pentair TR100C filter with glass media and a new multiport valve. Everything was installed yesterday and pool's been running for 24 hours now.
Pool was shocked by 25lbs of Calcium Hypochlroite - Ultimate TKO brand (it was completely green and now it is cloudy)
here are the number (Taylor 2006 kit):
FC: 13.0
CC: 2.5
PH: 9.6 (Taylor kit cant go above 8 so I used a digital meter which I know is accurate)
Alkanity: 90
CYA: 35
Calcium Hardness: 180

Pool's been running for more than 24 hours and I have not seen any increase in pressure (filter gauge) at all yet.

What would be the recommended next steps to clean up the pool water.

 

[YippeeSkippy]

Sim, you have a chemistry problem as evidenced by those 2.5ppm of CC's. You need to stop using calcium products as a sanitizer and just use plain, unscented bleach/liquid chlorine.

I hope your new filter helps clear the dead algae out, but I've read some folks have displeasure with the glass media. Let us know how it works for you.

Have you read Pool School yet? Start here- ABCs of Pool Water Chemistry and Pool School - Recommended Pool Chemicals

Then bone up on the SLAM procedure--> SLAM Process

Maddie

 

[Sim]

thanks. should i fix ph first or keep working on chlorine?

Last night my FC was 1.0 and CC was 1.0

I used 4 large jugs of bleach (6%) last night and my number this morning was FC: 8.0 CC: 0.5 (i underestimated the amount of bleach needed (used calculator later) and will get more today).
should i raise FC to 14.0 or work on ph now (ph is 9.2)

Pool's been running non stop for 3 days now.

 

[Sim]

Final update, people who may come across this thread and had same issue as me may find this helpful.

- I fixed the PH first (used Muratic acid from local store and it was cheap and effective). I allowed FC to drop to 1.0 before adjusting PH as the forum said that ph can be incorrect at high FC level.
- Next I raised the FC levels to between 8 and 10 and tried to keep it there till my CC came below 0.5. Used Cheap Bleach from my local Cash & Carry (called Smart and Final in CA), it cost me under $1.50 a gallon (6%) and i used up around 15 gallons over a period of a week.

Pool was clear within 10 days. Ran it non stop for first 5 days and ten 16 hours for next 5 days.

Thanks to all who helped out with comments and I love this site and the collective knowledge it presents, the whole Bleach thing is awesome. Never going back to useless expensive stuff.

My CYA came down (below 20) in the whole process, I am not sure why. Working to raise it now.