Replacing media in a sand filter -- should laterals be replaced too?

[largesock]

I'll start with background because I never seem to give enough initial information when I post on this forum. TLDR at the bottom.

I bought a new house with a pool last winter, and am trying to get it fully operational now. After getting the water chemistry settled, all the green/brown tint from the nasty water cleared up, and FC levels stay up overnight, so I think I've killed all the algae, etc.

However, after letting the filter run for two weeks now, the water is so cloudy I can't see more than about a couple of inches into it. I've tried SLAMming it up to about 20 FC for a few days with no apparent change in water quality.

So I concluded the sand is probably shot and I should try new media in the filter. I have no idea how long the sand has been in use.

TLDR: I called a local pool place to get the media replaced. They wanted a picture of the filter to order laterals. I've seen no indication of sand in the pool (we did swim in it, so I've walked around in the shallow end barefoot, and felt the water coming out of the jets). My immediate reaction was that this is a red flag -- they're replacing the laterals even when not necessary so they can rip me off. Am I right? Or is it standard practice to just go ahead and replace laterals when swapping out the media?

 

[mknauss]

First, sand does not wear out. It may need a deep cleaning, and if floc or clarifier have been used it may be clumped together, but normally it never needs to be changed.

I do not believe laterals need to be changed unless they are compromised. Now a pool service may not want to take the care to save the existing laterals and just bust up the old ones when taking the sand out and charge you for new ones. I do not know.

It sounds like you did not follow through the entire SLAM Process. But before you restart it, you should look at Deep Cleaning a Sand Filter and consider deep cleaning your sand first. If you find it clumped and you are unable to gently clean it, then consider having it changed.

 

[Richard320]

Before you open that new sand can of worms, reread the SLAM Process Did you pass all three tests? It doesn't sound like it. Also, did you read the part that suggests you add DE? When you aren't vacuuming up anything and the bleach consumption has normalized, then it may be time to improve the filtration. Bring the time down to a couple days rather than a couple weeks.

In my experience here over the years, too many people stop too soon and never really get their pool crystal clear. It's too easy to blame the sand. That's why pool stores do it. Plus they get a good sale. You gotta ask yourself how is it that this sand is a million years old but you managed to wear it out.

Anyway, to address your question... it's not absolutely necessary to replace the laterals. My gut feeling is that this pool store has dealt with too many old brittle pieces that break if you look at them cross-eyed, so now they just plan to replace them. They may have to tug on things pretty good, and I can easily visualize them snapping. It's better to have the parts on hand rather than get stuck with a 3 week backorder.

If you try adding DE and you end up with a white plume entering the pool, then you have channeling. The sand has clumped into clods and backwashing jumbled them and now you have huge crevasses where the water flows without being filtered. The solution for that is Deep Cleaning a Sand Filter

 

[largesock]

Any good step-by-step guides for getting into the sand filter for someone with almost 0 plumbing experience? I've not looked into it myself because I'm scared I'll never get the plumbing leak-proof again if I do. There aren't any threaded attachments between pipes to undo -- it seems to me like I either need to remove some glue and yank a pipe right out of the multiport filter, or hacksaw something apart to get into it.

To put it bluntly, I have more money than time (small kids at home and a full time job), which is why I wanted the pool place to deal with it in the first place. But I didn't want to pay for unnecessary laterals either.

 

[largesock]

Oh, and FYI, the sand being a million years old seems like a disingenuous argument against replacing it. I have no trouble believing that my subjecting it to extremely high water pressure on a constant basis would weather it many orders of magnitude faster than if it was sitting undisturbed underground. What is Silica Sand? - Select Sands Corp

 

[Richard320]

If time is more important than money, hire the pool store. I think they're being prudent to include new laterals. Maybe they won't use 'em and it'll end up costing less. Who knows? As a mechanic, I never had one customer get mad if I was under the estimate. They'll also want to saw the pipes and glue in some unions. Next time it will be easier for you.

The article on deep cleaning has some pretty good directions on opening up a filter.

Let us know how it works out.

Update: I looked back at history, and it appears your pool used to use Bacquacil. Did you not change the sand at the end of the conversion? If not, then by all means replace it.

 

[RDspaguy]

I always recommend replacing laterals when changing sand. Fresh sand can oulast old laterals by many years, but you can't change laterals without removing the sand.

 

[largesock]

Thanks for all the feedback! I'm glad to hear the laterals are a reasonable thing to change out.

I'm having them put in some unions so I can do some more maintenance on it in the future.

PS: The Baquacil pool was at my old house, so different setup. It was a wonderful pool though -- took an absurd amount of bleach to convert it, but it was worth it.