Paver joints a riskier source of algae?


Gold Supporter
May 17, 2018
Clermont FL
Just curious if the experts in this TFP community think paver joints are a higher risk for seeding algae in pools. We have a screen enclosed pool with a paver deck. Some of the joints are a bit black (with moss?) even though sealer was used and I hit them with bleach from time to time. I’ve managed this year old pool with the TFP algorithm and its been great although I am now suspecting some rising chlorine usage even as the weather moderated. I have had to dial up my SWG % to get the same levels even though the water looks fine so far and no CC. Doing OCLTs in case and for now keeping FC higher in range. This seems to have possibly started after the last big rain we had a while back. The deck drains and drys well but I would guess that the biological stuff from paver joints could find a way in on feet or by splashing. So if indeed I have to SLAM I’m still wondering about the source and possible high inoculum potential from paver sand joints and about disinfecting the Crud out of that too. I like pavers but is this a consideration in choosing pool decks vs concrete etc.?


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
Algae spores are airborne for the most part and are a part of virtually every environment. While the grout in your pavers is a nice home for algae, it will also be delighted to grow in your pool, too, if the conditions (not enough chlorine) are right.

Algae in your pool and in your paver grout are separate issues.....mostly unrelated. Adequate chlorine is the answer for both, however.
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Gold Supporter
May 17, 2018
Clermont FL
Post your water chemistry...

Water temp

Normal water chemistry should deal with algae that gets swept into pool.
These are my usual ranges FC and pH taken at least twice daily morning and late day. TA every other day or so, Other numbers less frequently.

FC 3.5-5.5
pH 7.5-7.8
TA 50-70
CH 425-475
CYA. 40
Borate 45 with liquid titration test
Salt 3200
Water temp 82-90

This morning the OCLT was 0.5 so I may be OK not to SLAM but will keep doing this.

The concern was FC dropped down to 2 a week or two ago surprisingly a week after the last big rain. I had to dial the SWG up from less than 10% to 20% then 30% running 9-5. I have been keeping at FC 5-6.5 last couple days. It may have been an anomaly. But I usually had to keep the SWG 10% or less running at 8 hrs or less to be at 4 even in full sun.... I do run the VS pump on at least low 24-7.