Best practice closing a Fiberglass EcoFinish pool?


Active member
Jun 9, 2016
Hi All,

This year due to industry gelcoat issues with my fiberglass pool I had EcoFinish sprayed in as a solution. I just recently had another layer sprayed in due to some fading/chalking issues that may have been caused by my chlorine habits. Mainly running higher chlorine than the recommended 1-3 ppm and shocking a few times with Cal-Hypo. I was also told to not adjust calcium hardness and let it stay low. So going forward the plan is to disregard the calcium, use on non-chlorine shock and keep SWG between 1-3 ppm. I am trying to get my head around taking care of this pool with the new finish and close it properly without screwing up finish come next spring.

So I have a fresh layer of EcoFinish and I have filled to my winter level with tap water. Checked pH and adjusted down to about 7.2. TA was 35, CH 30. I have a closing kit called Nu-Clo from local pool store that has 2 lbs algaecide, 2 lbs alkalinity and 2lbs dichlor. I mixed the 2lbs algaecide in a bucket and broadcast into the pool, dropped in the 2lbs Alkalinity winterizer and mixed 1lb of the 2 lbs dichlor in a bucket and poured in. My pool is 10,000 gal but probably 5,000 gal or so in it now so I halved the diclor. Swished it around good and ran pump to mix. I checked FC and its 11 ppm now. My concern is bleaching the EcoFinish again immediately and over winter with the high FC. I know it will come down and has already since it is being used and I also have not adjusted up CYA since tap water refill but is this EcoFinish that sensitive to dichlor chlorine shock? Is the only way to go non-chlorine shock now during season and for closing\opening? To get this FC don I have drained pool down some and added more water to dilute. I may be over cautious here but if EcoFinish is this delicate it may not be a good choice for me. The info I am getting so far is not crystal clear or straightforward.

I was told to definitely stay away from Cal-Hypo and disregard raising calcium with this finish. I guess my question is what Is proper best way to now close my pool with EcoFinish surface? Since I have put dichlor in I have been trying to dilute to a point to not cause bleaching. Any advice or experience is greatly appreciated. I am trying to establish a routine again and do it right so as I am not the cause of a costly mistake.

Thanks for your help.



Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Put at least 30 ppm of stabilizer in your water. The CYA buffers the chlorine and only a small portion is active chlorine. That's why we can say that up to SLAM FC level - 12 for CYA 30 - is safe to swim in and would be safe for you finish.

FC/CYA Chart