Recommendations for cedar wood tub

[emewilli]

Hello, I'm a newbie to hot tub ownership and really appreciate all the wonderful advice I've found here. So, first off, thank you to everyone.

My question: I have a new-model old-school cedar soaking tub (I think I got all the right specs in my signature per the forum guidelines) and am looking for any advice folks might have specific to them. I'm aware of some of the down-sides of wood tubs (more expensive to heat and maintain, prone to leaks), but love the look and experience so I went for it. I've searched but haven't seen anything on TFP forums regarding special considerations for wood tubs... Does anyone have any advice? Should any of my levels or products be different from the standard in any way?

My routine: I really enjoy the "pet-ownership" aspect of my tub and am having a blast testing most days and trying to keep all the levels optimized as suggested in Pool School and the forums here. My boyfriend says I'm one step away from turning into Walter White from Breaking Bad, what with all my testing reagents, chemicals, and gear for handling the muriatic acid and such. The day I made my own Soda Ash by baking Baking Soda in the oven he was just plain speechless. Anyway, I'm draining and refilling quarterly, at which time I've been lightly washing the inside, teak oiling the outside, and mineral oiling the top lip. All of which was recommended by the manufacturer and the one guy in the area I could find with actual experience to install it.

My numbers: I have a Taylor test kit; using dichlor and bleach; have added Borates. Current numbers are:
FC = 2 (resting level right now; I add more when folks are coming over and always after soaks... personal pref I'd rather it on the low side if I can?)
CYA = 10 (I know that's a little low, but it's always covered during the day since I practically only soak at night so UV isn't an issue... right?)
pH = 7.5
TA = 80
CH = 180
Borate = 50ish (my LaMotte Borate test strips haven't arrived yet, but I added the amount the Pool Calculator recommended, so it should be very close)
CSI = -.06 per Pool Calculator

I apologize if I've forgotten any relevant details. Thank you so much for any advice or recommendations on keeping my cedar baby in tip top shape!

-Emily

 

[gtemkin]

I've been considering a cedar hot tub so I'm very interested in any guidance you receive.

Have you seen much wood deterioration from your chlorine use? Some sites warn against chlorine for wood, some promote it.
Is your quarterly refill instead of shocking or is it just something done with stand alone hot tubs?
Is the calcium level a result of the fill water or do you add calcium to achieve. Do you know if calcium is needed for a wood hot tub?

Gregg

 

[emewilli]

I've only had the tub myself for 8 months. However, before that it was owned by some close friends so I saw a lot of it then, too. I haven't seen any concerning deterioration over the years. When I wash out the inside when I've done refills (only done two) there's been a little bit of cloudy residue that washes off the wood, but nothing that seems weird. The top of the boards is a little soft in spots where the cover rests on it, as is the bottom of one board in one spot where I think some debris was against it for too long when my friends had it. But that's not from chlorine in particular, and from what I've read that's hard to get around and you just keep an eye on it.

I've been mostly following the recommendations of the manufacturer (Sea Otter Woodworks, http://woodentubs.com/hottubdetails). They seem to generally promote maximizing tub life by minimizing chemical use by: keeping the cartridge filter super clean, using a copper ionizer to maximize the efficacy of minimal chlorine levels (which I do because it came with the tub... seems to be some science behind it... not going to stain the wood... though I'm not sold), and using granulated chlorine (dichlor) instead of bleach (which I do unless the CYA starts inching up).

I think the quarterly refill recommendation is standardish for hot tubs, plus it forces you to inspect and wash the wood inside and out. I had been shocking weekly with MPS, but I think that was overboard given my bather load and what I'm seeing in my CC and FC overnight tests now with the Taylor kit. I'm still figuring that whole part out.

The calcium I didn't get any wood specific insight on. The literature that came with the tub's pump/heater recommended the same CH levels I've seen elsewhere, but it wasn't in a wood specific part of the instructions. So I put in the calcium raiser liquid stuff since it seemed the safe thing to do. I'd love to know if there are specific ranges that are good/bad for wood like there are for plaster. It was actually the info about calcium levels and plaster that made me start to wonder about whether wood had any special needs like that.

Anyway - I know I'm a newbie and probably doing something unintentionally wacky - would love input!

 

[gtemkin]

It sounds like you've done a lot of homework and I don't think anything you're doing is wacky.

On the calcium thing, I have a very beginners understanding of it all, but I think the calcium has two primary benefits. The first is that it satisfies the water in plastered pools to prevent leaching and weakening of the plaster layer. Since you don't have plaster that wouldn't pertain to you. The second reason - and I guess this may not be accepted by all - is that a small amount of calcium is needed to protect metallic components that are in contact with water (heater) and act as a protection buffer during brief periods where your water may go slightly out of balance. I'm thinking that's why a 50ppm CH is recommended even for fiberglass pools. I don't think maintaining the 180ppm CH is harmful; it's just that you can enjoy the benefit of a very broad CH range.

Again, I'm far from having specific expertise beyond my own pool and I'm hoping someone would step in and correct me if I'm passing on bad info.

Gregg