General questions on Bleach

[newtubuser413]

I bought brand new hot tub since December.  Used it 2-3 times a week on weekends since then and kept up on TA and FC levels, but only using MPS and Chlorine Granules.  Changed filter two weeks ago and added some water to top off.  Started getting rash (wife did not).  I don't know the cause...thought it was new filter at first or maybe water was dirty when I did top off.  Read up on this forum and basically learned about biofilm.  In the midst of going through decontamination sticky.  I don't know exactly what caused the change but it may be because I am not using the bleach method and my CYA is too high and maybe that prevented my FC from activating or whatever (still learning).  Using Ahhsome now and after I purge the hot tub, I plan to use the bleach method.  Question:

1: Any thoughts on direct cause of rash?

2: I can't find 6% bleach...only find 7.5%.  Is that ok?  Can anybody link me to the right bleach to use?

Thank you in advance...I'm new at this and am learning as I go along.

[waterbear]

3 hours ago, newtubuser413 said:

Any thoughts on direct cause of rash?

either contact dermatitis from the MPS or hot tub itch caused by Pseudomonas infection  from the high CYA not permitting the chlorine to effectlvely kill the microbes in the water.

[waterbear]

3 hours ago, newtubuser413 said:

I can't find 6% bleach...only find 7.5%.  Is that ok?  Can anybody link me to the right bleach to use?

You can used either liquid pool chlorine, which is 10% OR 12.5% sodium hypochlorite, or use household chlorine laundry bleach such as Clorox, usually 5.25% or 6%, as long as it is not scented, thickened or splashless, or has any cleaners or detergents in the formulation . The ingredients might list water, sodium hypochlorite, sodium chloride (salt), sodium hydroxide, sodium carbonate, and (for laundry bleach) polyacrylic acid (used to prevent soil from redepositing back on clothes and is also the main ingredient in many polymeric  pool and spa clarifiers so the small amount in the bleach will NOT have any negative impact on your water). These are either added to stabilize the bleach or are the result of the manufacturing process and are a normal part of the makeup of bleach or liquid chlorine. I have personally never seen 7.5% bleach but 8.5% was commn a few years back.

The ONLY differences between the different strengths of sodium hypochlorite is how much is needed to reach a given FC level in a given volume of water and the shelf life of the bleach. The more concentrated strengths need less to achieve a given FC level in a given volume of water and have a shorter shelf life before they start to degrade and lose strength. There is no reason you can't use old bleach as long as you are testing the FC and adding enough to achieve the desired level.

[newtubuser413]

Thank you so much.  I got a long day ahead of me to try to disinfect

[newtubuser413]

Ugh...🤮

this biofilm is so sticky and hard to get off.  Any ideas or is this just gonna take elbow grease?  I’ve been using bleach wipes as my paper towers have been ripping.

[RDspaguy]

Ewww! That's some nasty looking crud. 

Your filters should not be installed when using Ahhsome. Just float them in the tub.

@Ahhsomeguy, have you ever seen that sort of nasty?

[Ahhsomeguy]

Hello RDspaguy:  This is very typical.  We have seen so much worse than this.  You are correct, you MUST remove the filter(s) while purging or two things happen.  The water flow is greatly diminished and the purge is compromised and second, the filter(s) do their job and clog up quickly if the bio-fouling is present.  People have to read the instructions.  They usually use too much gel to do the job as well.  The good news RD is that hot tub owners are beginning to listen.  Manufacturers and dealers are beginning to mention biofilm more often and are not as afraid that doing so will decrease hot tub sales.  Actually the opposite is true.  When consumers are educated about the benefits of periodic purging and draining hot tub water they find that the water clarity and maintenance issues are better and much easier.  

[RDspaguy]

I have worked for dealers that would open up the packaging and stand up the tub to drain out the nasty before bringing it to the customer so they wouldn't see what came out of the pipes. They didn't bother to do anything with it, but definitely did not want the customer to know.

[newtubuser413]

@Ahhsomeguy @RDspaguy Yes, I did remove the filter and left floating in there.  What you see is what happened, in that the crud stuck to the filter (floating, not installed).  I deviated from the instructions in that I left it overnight (per Nitro Decontamination process) instead of 15-30 minutes, which is probably why the amount of crud got stuck to the filter that you see in the picture.

My question is, why even have the filter in there anyway?  Why not just take it out and set it somewhere during this purge process.

[newtubuser413]

@waterbear What I got from Target today

[Ahhsomeguy]

To Newtubuser413:  The reason we like to have the filters placed INSIDE the hot tub proper while purging is to aid in the removal of gunk that may be lodged deep within the pleats.  Filters can harbor bio-contaminants as well.  Note:  we do NOT recommend that you leave Hot Spring Ceramic filters in the tub while purging or any type of "throw away" disposable paper type filter cartridges.  Please let us know if the problem you are encountering is better after the next cleaning.  Thank You.

[waterbear]

11 hours ago, newtubuser413 said:

 What I got from Target today

Perfect! However, you will need to do a bit of trial and error to determine dosing levels so add the amount you think is needed to raise the FC to target and then test to see if you are right. You can make adjustmets until you zero in on how much to add for a specific FC level in YOUR teb.

for every 100 gallons of water adding 1 tablespoon of:

5.25% bleach will raise FC by about 2 ppm

6.0% bleach will raise FC by about 2.5 ppm

8.25% bleach will raise FC by about 3.3 ppm

10.0% bleach will raise FC by about 4 ppm

12.5% bleach will raise FC by about 5 ppm

so I would expect the 7.5% bleach will raise FC by about 3 ppm

(these numbers are not exact but are in the ballpark. They have been rounded to make measurements easier but should be close enough to get you where you want to be or very close to it)