Green Hot Tub Water – Why It Happens and How to Clear

Green Hot Tub Water – Why It Happens and How to Clear 

If your hot tub is filled with green water, it’s not just unappealing; it also prevents you from using it safely. It implies there’s a chemical imbalance, and that the water isn’t safe to use. If you have ever had an algae bloom in your hot tub, then this article will answer all of your questions regarding why and how to remove it! 

What Makes Hot Tub Water Turn Green 

Lack of Sanitizer in the Water / Algae Growth 

The most likely scenario is that there isn’t enough sanitizer (chlorine or bromine) in the water, and algae is beginning to develop and flourish. This may be due to lack of attention to the water over a long period, heavy usage which has resulted in the sanitizer dropping quickly and/or something affecting the sanitizer efficiency dramatically. 

Excessive Metals 

This could be due to a lack of attention to the water for an extended period, much usage that has led to the sanitizer being depleted rapidly, or something affecting the effectiveness of the sanitizer. 

How to Clear Green Water from a Hot Tub 

Shock the Water and Clean Filters 

To eliminate green water, you must first destroy any prospective algae development and then give the water a thorough clean in order to try and restore it to a level where sanitizer levels of 3-5ppm may be maintained. Add chlorine or bromine granules to a hot tub with a free chlorine or total bromine level of 10ppm to reach a 50g dose for a 1,000L hot tub.  

You should notice it clearing after a few hours. At this point, it’s worth cleaning your hot tub filters to make sure any dead Algae is removed from the water. 

Drain and Refill 

If you’re unable to clear up the water using the technique described above, and you want to start over, you may totally drain and refill with fresh water. Add 5 ppm chlorine to the water and wait 1 hour before flushing out the pipes with a pipe flush. This will guarantee that any algae that may be lurking in the pipes is destroyed. 

If you’re worried about pollutants in the water, consider using a pre-filter like the Hot Spring Clean Screen to remove metals from the source water, eliminating any chance of a green tinge caused by metals. 

Tips to Prevent Green Water in a Hot Tub 

• Ensure your levels are always within range – Chlorine/Bromine 3-5ppm. PH 7.2-7.6. Alkalinity 80-120ppm. 
• Use a pre-filter when filling if concerned with metal content in the water. 
• Keep your filter clean and degreased using a filter cleaner. Filtration assists with sanitization.  
• Drain your hot tub every 3-4 months and use a pipe flush to remove biofilm.