Backwashing sand filter with a Salt Water pool

gtduck

Member
Jun 16, 2020
10
Newnan, GA
We're having a fiberglass pool installed here soon (come on builders) and are trying to plan many things out. One thing that's come up is that I will need to backwash my sand filter (this is our first pool, so please forgive the initial ignorance). We're on septic so that's not an option and while there seems to be mixed messages on the legality of it or not, I'm not overly interested in backwashing into the street drainage system.

My question is my pool equipment pad has will have Bermuda grass around it and could potentially have a flower bed (that I would plant with salt tolerant plants.). Am I going to mess up my yard by backwashing into it?. I've seen a number of people on this forum stress that the level of salt in the salt water really isn't that high. My other alternative plan is to rent a trencher from Home Depot and hard plum my backwash line up to the back of my property and to then install a popup emitter back there (where I don't really care about the grass/weeds/etc). Thanks for any thoughts/advice that people may have.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Am I going to mess up my yard by backwashing into it?.
It's possible, but it may not be the salt. The chlorine may influence it as well. Hard to know for sure since grass type, soil conditions, moisture, water chemistry, and probably some other factors come into play. To be safe, I would make plans to run your waste water to an isolated area that won't bother you if it does impact the grass. Good luck on the build.
 

gtduck

Member
Jun 16, 2020
10
Newnan, GA
It's possible, but it may not be the salt. The chlorine may influence it as well. Hard to know for sure since grass type, soil conditions, moisture, water chemistry, and probably some other factors come into play. To be safe, I would make plans to run your waste water to an isolated area that won't bother you if it does impact the grass. Good luck on the build.
Sounds good. Thanks for the advice.
 

Chrissykr

Well-known member
Jun 8, 2014
608
Rogers, AR
I have Bermuda and it never bothered it. Mine was on a slope and did more damage washing it out than anything. I had mined changed last year to go into a drainage ditch behind my yard. That was the best thing we could have done.
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
898
Verona, MO
We also back-flush into the yard and haven’t had any issues even when draining down to close the pool.
Fescue and bluegrass
...and a few weeds. 🤣
 

proavia

LifeTime Supporter
TFP Guide
Feb 6, 2015
1,955
Chandler AZ
Or you could just change from a sand filter to a cartridge filter and not have to worry about backwashing. Be sure to oversize any type filter you get - that way you can extend time between cleanings.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,204
Tucson, AZ
Ummmm....why are you getting a single speed pump with an SWG?

SWG's produce chlorine very slowly and so you have to run your pool pump for a lot longer. Some simple math with your pools specs - the IC40 will generate about 0.5ppm FC in your pool volume per hour at 100% output. However, it is not advisable to run SWG's at 100% output. SO if you use 50% output that gives about 0.25ppm/hour. A typical swimming pool can use up to 4ppm/day. So your SWG will have to run for 16 hours per day to make up for the FC use. A 1HP single speed pump can use a lot of electrical power (well over 1kW) depending on your plumbing. A variable speed pump is a MUCH better option as it can be dialed in to run at the lowest speed possible that activates the SWG (SWG's must have the pump running and typically need a flow rate of greater than 15GPM to activate the flow switch).