Using both Tri-Chlor and Liquid Bleech


Active member
Aug 6, 2010
Does anyone have an opinion or actually use a Tri-Chlor feeder for convenience for adding everyday chlorine and then use liquid bleech when you need to schock so you don't add and more cya or calcium when you shock.


Well-known member
Jun 12, 2010
NE Ohio
I think a lot depends on circumstances. I am seriously looking at converting to the BBB method but everything is running so well right now I'm not going to change anything this season.

However I have had my pool for 4 years and basically used pucks and HTH "shock" for my chlorine source. I think the reason it works for me is that the pool is really only "open" for about 4 months and sees high usage for maybe 3 months. I use very little chlorine so the convenience factor is outweighs other factors. I never seem to get much higher than ~ 40 ppm CYA; probably because I drain a bunch of water every year when I close the pool.


LifeTime Supporter
May 19, 2009
Dallas, TX
If you keep your FC in check according to the FC/CYA Chart you never need to shock regardless of chlorination method. :goodjob:

However, if your FC gets low for your CYA level and you get algae, and in addition you have a high CYA level from excessive trichlor use, better go buy a pallet of bleach to clear it... :thumbdown:


TFP Expert
LifeTime Supporter
Nov 5, 2008
You can use trichlor tablets sometimes. You can use calcium hypochlorite sometimes. You can use dichlor powder sometimes. You can use bleach pretty much all the time. The key is to test the pool often enough to know what you can afford to use.

If CYA is a little low, you can choose to use trichlor tablets to slowly raise CYA. If CYA is a lot low, you may choose to just add CYA to get it to a minimum level or to the recommended level or to the maximum level, depending on what chlorine source you intend to use next.

If CH is a little low, you may choose to use cal-hypo to slowly raise CH. If CH is a lot low, you may choose to just add a calcium increaser to get it to a minimum level or the recommended level or to the maximum level, depending on what chlorine source you intend to use next.

Once CYA and CH are where they need to be, then you will need to go to using 6% bleach or stronger liquid chlorine as your main source of chlorine. Both CYA and CH will tend to drift downward over time in most pools, though if your fill water is high in CH then that won't fall unless you get a lot of rain.

If you keep on top of testing and knowing how your water changes over time, with rain dilution and with fill water additions, with the changes in temperature and pool usage, then you can easily shift between various sources of chemicals. You just need to keep records and do tests often enough to be certain of what is going on.

For some, it is best to just use bleach and add CYA and calcium directly when it is needed, all at once and be done with it. Then use just bleach to add chlorine. Separate chemicals for separate needs. For others, it is no big deal to tinker with the blended chemicals, adding chlorine with CYA, or chlorine with calcium, until the chemicals are as needed.

But I will say that no matter how good you are at taking care of your water, you may still need to shock... emergencies do happen. Several days without power, massive rainfall, nasty things in the pool, you never know. So it is good to always have a good dose of something on hand in enough volume to shock properly. I keep cal-hypo for that, since I tend to run with high CYA in the summer heat here in Texas and I can better afford a small 10 ppm bump up in CH than I can afford a 10 ppm rise in CYA. Rain will take the CH level down before too long.