Intex inflatable Hot tub has black carbon flakes in the water

Red Shirt Ensign

LifeTime Supporter
Mar 10, 2011
192
#1
Hi,
We bought an Intex Inflatable Hot tub last season and towards the end of last season and with the beginning of this season, the water being inlet into the spa through the Heating stage, is releasing these small black dots that float and sink in the water. I assume they are carbon, maybe some corrosion adhering and flaking off the heating element? If you use a Vicks vaporizer you are left with the same similar black flakes, which makes me think its carbon.

when you rub it in your fingers it smears and goes away in water.

Is there something in my water balance that I can do to stop these flakes from getting in the hot tub? Many of the particles are finer than the the typical pool wand and I have to put a panty hose over the skimmer to actually catch them up.

I'm also worried that over time this will shorten my heater life

Any thoughts?

Thanks
Dan
 
OP
OP
Red Shirt Ensign

Red Shirt Ensign

LifeTime Supporter
Mar 10, 2011
192
#5
Would increasing calcium hardness help protect the heating element and prevent flaking. I know my CH needs to be a certain level in the pool to protect my pool heat exchanger.
 

MTMommy2

New member
Jul 16, 2013
4
#9
I have these, too, in my Intex hot tub. I have slammed it several times and used algacide twice and changed the filters. I had it inside for the winter, had the power flip off and they appeared. I meticulously cleaned it after draining, including what lines I can get to while taking it apart to move outside. Refilled and still have them. And yes, they dissolve into a carbon smudge when touched and don't seem to filter out to dirty the filters not strain out well. Red Shirt Ensign, did you ever find a solution?
 
Jul 22, 2017
2
VERMONT
#10
I also have the same problem. It started when I switched to bromine. Called intex and they insisted I can’t use bromine with this Hot Tub but couldn’t give a reason why. I emptied the tub and went to an all chlorine system and the flakes never came back. I’m have quite a time trying to figure out what’s going on if it’s deterioration in the heating element falling off or something in the lines but the tub is only 3 months old. Mean time intex is sending me a new control unit thinking the unit is bad but I’m starting to think it’s the water. We have very hard well water with lots of iron. Anyone else using bromine in their tub? ***Never Mind, after 2 weeks on straight bleach/chlorine the flakes have come back. Im at a loss***
 
Jul 22, 2017
2
VERMONT
#11
Well, Problem solved. For me at least. When the problem started a month ago I took the entire base unit apart to look for deteriorating o-rings but found nothing. Since the problem has returned in the last week I took the unit apart again only to find the pump/heater unit was melted and warped. Parts of it were flaking so the interior gasket must be melted or deteriorating. Whats worrisome is the tub is only 3 months old. Intex is sending me a new unit, well see how long it lasts.
 

Monte1985

New member
Aug 12, 2017
1
Boston/NY
#12
Had this problem with my old tub I had and new one I have now. I think it's the hoses they use to connect the far intake filter. When I warrantied my old tub I cut it open and there are 3 separate hoses that run from the far intake filter and they are rubbery. I think the bacteria builds up in there and eats away at the hoses and the spits the stuff out. I made a pvc cap with a filter to screw on the end of the jet that puts water back in the tub so flakes don't spit out.
 

MTMommy2

New member
Jul 16, 2013
4
#13
Had this problem with my old tub I had and new one I have now. I think it's the hoses they use to connect the far intake filter. When I warrantied my old tub I cut it open and there are 3 separate hoses that run from the far intake filter and they are rubbery. I think the bacteria builds up in there and eats away at the hoses and the spits the stuff out. I made a pvc cap with a filter to screw on the end of the jet that puts water back in the tub so flakes don't spit out.
Can you please elaborate on how you did this? How did you use a filter with a PVC cap? Did you use something like a wire mesh screen, like a household faucet would have? Thanks. I am now considering some sort of in-line filter.

It has required extensive cleaning to rid my tub of the carbon flakes. Mineral spirits has been required to clean the ENTIRE TUB, filter housings, screw-in screens, EVERYTHING. Bleach, Dawn Aah-Some cleaner (run through the whole tub as well as on a toothbrush undiluted) HAS NOT even touched it. This stuff is greasy. If this is some sort of biofilm, it baffles me. I favor the carbon from something breaking down. I have taken many places in my pump "box" apart and I have seen no evidence of anything black. I am considering one more look before I fill it back up with fresh water and I am not sure where to look. If anyone knows how to access the heater area, I'm grateful. This thing has been one huge pain in the booty!
 

Bossman315

New member
Dec 6, 2017
2
GALLITZIN PA
#14
Hi,
We bought an Intex Inflatable Hot tub last season and towards the end of last season and with the beginning of this season, the water being inlet into the spa through the Heating stage, is releasing these small black dots that float and sink in the water. I assume they are carbon, maybe some corrosion adhering and flaking off the heating element? If you use a Vicks vaporizer you are left with the same similar black flakes, which makes me think its carbon.

when you rub it in your fingers it smears and goes away in water.

Is there something in my water balance that I can do to stop these flakes from getting in the hot tub? Many of the particles are finer than the the typical pool wand and I have to put a panty hose over the skimmer to actually catch them up.

I'm also worried that over time this will shorten my heater life

Any thoughts?

Thanks
Dan
Did you ever solve this. I just got done talking to Intex and the agent tried telling me brominating tablets were eating my wires of the base unit causing this, but couldn't be specific as to which part it was or transfer me to a supervisor. lmao, called local spa pool place and they suggested spa guard oxidizer enhanced shock. Triple dose. Gone, worked great for my issue. Going to check levels today and adjust as necessary.
 
May 18, 2018
1
burbank,ca
#15
I have the intex inflatable spa as well, I had my pump fail (e90) before the 1st year. Contacted intex and they send me a replacement base. I take things apart for fun, so I was going to discard the base and last night decided to perform an autopsy on the faulty base. The black that you are seeing, from my observation isn't carbon. The Heat Exchanger assembly is painted black inside and out, the aluminum was so corroded that the paint started to flake off and blocking the flow through it. The impeller on the water pump is made of ceramic. That failed a few months before (broke in two places and was very worn out), I replaced it with a titanium shaft which also became very worn out. Flow Sensors seem to be functioning. Hope this was useful. Would love to know if anyone has figured out what can be used that will survive, when this one inevitably dies.
 
#18
Had this problem with my old tub I had and new one I have now. I think it's the hoses they use to connect the far intake filter. When I warrantied my old tub I cut it open and there are 3 separate hoses that run from the far intake filter and they are rubbery. I think the bacteria builds up in there and eats away at the hoses and the spits the stuff out. I made a pvc cap with a filter to screw on the end of the jet that puts water back in the tub so flakes don't spit out.
Wow...excellent investigating, innovating, and troubleshooting...has it gotten better? I have the same black flakes and they are getting worse.
 
#19
I have the intex inflatable spa as well, I had my pump fail (e90) before the 1st year. Contacted intex and they send me a replacement base. I take things apart for fun, so I was going to discard the base and last night decided to perform an autopsy on the faulty base. The black that you are seeing, from my observation isn't carbon. The Heat Exchanger assembly is painted black inside and out, the aluminum was so corroded that the paint started to flake off and blocking the flow through it. The impeller on the water pump is made of ceramic. That failed a few months before (broke in two places and was very worn out), I replaced it with a titanium shaft which also became very worn out. Flow Sensors seem to be functioning. Hope this was useful. Would love to know if anyone has figured out what can be used that will survive, when this one inevitably dies.
I too have an Intex Spa and my pump failed within 4 months...they replaced promptly. All was well with unit for about 8 months...now, I am getting sooo many black flakes it's crazy. My water is crystal clear, so I like your theory from your troubleshooting. Have you figured anything out? I know that draining and refilling won't 'fix' this issue...kinda frustrated cuz I love my hot tub...helps with my sinuses!
 
#20
Did you ever solve this. I just got done talking to Intex and the agent tried telling me brominating tablets were eating my wires of the base unit causing this, but couldn't be specific as to which part it was or transfer me to a supervisor. lmao, called local spa pool place and they suggested spa guard oxidizer enhanced shock. Triple dose. Gone, worked great for my issue. Going to check levels today and adjust as necessary.
So...how's it going? Was that oxidizer the answer?