I've owned a Northern Lights cedar hot tub for about 8 years and loved it. 4' deep and about 600 gallons. I've used an ozonator, bromide/bromine, MPS after bathing, and weekly di-chlor shock. Some experts say only bromine, others say NO bromine, use bleach. They all say one or the other can destroy the wood. Lots of opinions. This past year it developed a slime on all surfaces. I tried to take it off with fiberglass scrubby pads and they just clogged up with a white papery substance. The filters were clogged with a slimy white pulpy mess. After googling around I determined that it was white mold. After draining scrubbing, treating with di-chlor and drying out completely, I still couldn't get the residue out of the wood. I tried a light power washing even though I know that's tough on the wood. I ended up with a white/cedary/toilet paper like pulpy mess. Cleaned that up, dried with dehumidifier, sanded, new filters, filled, balanced water, shocked, and ran for a day testing continuously. Drained and repeated. Checked water just about every day, used tub 3-4 times per week, mold was back within a month. Repeated entire process and this time washed walls with 30% vinegar then filled with water, drained, rinsed, then repeated with bleach solution. Again, filled with water, balanced, shocked, etc. Mold was back within a month. I started super shocking with di-chlor (50ppm) and ran it for days/24 hour filter cycle, drained, rinsed, refilled, repeated. I also used a commercial pipe cleaning enzyme and took apart the plumbing at the unions to hose them out. Mold began accumulating in the filters within 10 days.
There is very little information on the web regarding white mold infestation in cedar tubs. From what I've gathered, the mold's roots penetrate the wood and feed on the sugars in the cellulose, then form a protective slime barrier making it hard for the sanitizers to get through. Figuring I wasn't getting to the roots, I repeated the process. I drained and ran dehumidifier at 40% humidity for a week. I knew it would shrink the wood but I'm desperate. I was left with bleached white powdery wood with some mold residue in the cracks and gaps. I'm sure alot or most of the white was from the chemical treatments. This time I removed the benches and jets to be able to completely sand the inside of the barrel and get to all the nooks and crannies in the benches. After the punishment of powerwashing, di-chlor, bleach, etc. some of the staves had a corduroy texture so I sanded with 60 grit to get the white out, then 120 to smooth it out.
I read somewhere in this forum or another that cedar, when treated with certain chemicals turns to paper. Now I'm wondering if I've been chasing white mold when all I was doing was burning the cedar with harsh chemicals and creating paper pulp (except for the slime that was forming everywhere). Now I'm in the middle of reassembling the tub, but wondering what is the best approach to sanitize for any remaining mold/spores before refilling. Some people mentioned that they didn't know anybody who was able to get rid of the mold completely and were considering an epoxy coating or fiberglass to seal the wood, not necessarily to seal for leaks, but to reduce the wood area the mold roots can cling to.
I have alot of hours invested and getting the same result. Nightmare.
Any takers?
Thanks
