What's your hot tub startup routine?

[Lys Grimes]

Just refilled my hot tub for the season and trying to get everything balanced, but it always feels like a guessing game. I add chemicals, test, adjust, and somehow still end up chasing pH and sanitizer levels for days. Is there a trick to making startup smoother? What’s your go-to process to get your water dialed in quickly?

 

[Derek Lawson]

I know that struggle. What helped me was adding alkalinity first, then balancing pH before adjusting the sanitizer. Otherwise, I felt like I was constantly chasing the right levels. If you are using chlorine, shocking after filling can help get rid of any lingering contaminants. What sanitizer are you using, chlorine or bromine?

 

[Brandon Hayes]

I used to go in blind too, but over time I found a process that’s made things way smoother.

Now, I always start by testing my fill water before adding anything. Sometimes your tap water already has high pH or alkalinity, and if you don’t know that upfront, you’ll be chasing numbers from the start. Once it's filled, I adjust alkalinity first, because that stabilizes the pH. After that, I dial in the pH and only then do I add sanitizer I use bromine tabs with a floater, but chlorine works too depending on your setup.

I also use a startup shock after the sanitizer to give everything a clean base. Then I test daily for the first few days just to make sure nothing swings too wildly. It’s still a bit of a balancing act, but doing things in that order really helps avoid the back-and-forth. Hope that helps, it definitely gets easier each time.

 

[Samuel King]

I’ve found that adjusting in small steps really helps avoid overshooting the balance. I like to check it every few hours just to see how it’s settling in after I add chemicals, and give it a little time to work before tweaking again

 

[Sean Whitaker]

Just refilled my hot tub for the season and trying to get everything balanced, but it always feels like a guessing game. I add chemicals, test, adjust, and somehow still end up chasing pH and sanitizer levels for days. Is there a trick to making startup smoother? What’s your go-to process to get your water dialed in quickly?

Yeah, that first week after refilling can be frustrating. Here’s what I usually do to get things running smooth without too much guesswork:

• Let the water circulate for a bit before adding anything. I usually run the pump for about an hour to mix everything up.
• I always check and adjust alkalinity first. If that’s off, your pH will keep jumping around. I try to get it somewhere between 80–120 ppm.
• Once that’s good, I move on to pH. If it’s too high or low, I fix it slowly over a day or two. No big rush — it needs time to settle.
• After that, I add my bromine or chlorine, depending on what I'm using. I don’t shock it yet — just let the sanitizer build up first.
• Once levels are steady, I go ahead and shock the water to clean out anything leftover from the refill.
• I test it every day for the first few days and adjust only if things are way off.

Also, if you always use the same water source, take notes — you'll get a feel for what works and won’t need to guess as much next time.

 

[Monica Cardona]

Just refilled my hot tub for the season and trying to get everything balanced, but it always feels like a guessing game. I add chemicals, test, adjust, and somehow still end up chasing pH and sanitizer levels for days. Is there a trick to making startup smoother? What’s your go-to process to get your water dialed in quickly?

To balance your hot tub quickly, start by testing your water to get a baseline. Adjust alkalinity first (80-120 ppm), then work on pH (7.4-7.6). Finally, add your sanitizer (3-5 ppm for chlorine or 3-6 ppm for bromine). Make small adjustments, test frequently, and allow the water to circulate for at least 30 minutes before retesting. Regular testing once a week will keep things stable and avoid constant tweaking.

 

[Amber Chase]

Hey Lys,

Totally feel you on that, getting the water balanced after a refill can definitely feel like chasing your tail for a few days. I’ve been through that loop more times than I care to admit.

For me, I’ve found the key is doing stuff in a specific order, otherwise, I’d just end up overcorrecting things and making it worse.

Here’s my routine (not saying it’s perfect, but it’s been working better the last couple seasons):

1. Fill with filtered water – I hook up a pre-filter to my hose when filling. It cuts down on metals and junk right from the start. Skipping that used to cause all kinds of problems for me later.
2. Let it circulate – I always give the water a few hours to run through the system before I touch anything. Usually let the jets go with the cover off to let any weird smells or foam settle out.
3. Test only pH and alkalinity first – Not everything at once. Alkalinity affects pH, so I start with that. If alkalinity is low or high, I fix that first and then pH usually follows more smoothly. Trying to adjust both at the same time just made me go in circles.
4. THEN sanitizer – Once pH is stable-ish (I don’t wait for perfection), I add chlorine or bromine depending on what I’m using that season. If you do it too early, you can burn it off fast if your pH is still out of whack.
5. Shock – One thing I learned the hard way: shocking right after refilling helps a ton. Gets rid of any organic stuff from the plumbing or even just the hose water.

From there, it’s just small tweaks. I test every day for the first 3–4 days just to keep it dialed in, then back off once things stay stable.

Also, I stopped stressing about exact numbers. As long as you’re in the safe range and the water’s clear and doesn’t smell funky, you’re probably good.

Anyway, hope that helps a bit! Took me a couple seasons to stop overthinking it.

 

[Kevin Marsh]

I’ve had the same “startup chaos” a bunch of times, and honestly the biggest thing that helped me was slowing down right at the beginning instead of throwing everything in at once. What I do now is let the water run through the system for a while before touching any chemicals, seems like the tub settles into its “normal” state after a couple hours, and it’s way easier to see what actually needs adjusting.

One thing I started doing last season that made a surprising difference is keeping an eye on how the water looks while everything is balancing out. If it even hints at going cloudy during the first day or two, I’ll add a bit of Aquadoc’s clarifier. I don’t know what kind of magic they put in that stuff, but it clears things up faster than anything I’ve tried, and it saves me from having to chase numbers for days afterward.

After that, I make tiny adjustments instead of big ones. If I try to fix pH or alkalinity in one shot, I almost always overshoot and have to correct again. But doing small tweaks and giving the tub time to react makes the whole process feel way less chaotic.

It’s never totally perfect on day one, but this routine has made my startups a lot calmer. Hope your next refill goes smoother too.