"Fishy" Smell Only on Hot Water Side - Lakewater System
Hi all,
At my wit's end here as I can't figure out how to solve the problem. Here's what we've got:
This is a new build, so all filtration components are new (~ 9 months of service). Water comes from a lake (actually a glorified river system). Filtration setup is:
- Spin-on sediment filter
- Iron Filter
- Tanin Filter & Softener
- 20"x4" sediment cartridge filter
- 20 x 4 charcoal filter
- UV Light (9 gpm I believe)
Cold water side of fixtures is flawless and has no smell/taste, save for a bit of algae growth in the toilet (oddly, the toilet that doesn't get used much has no algae growth). We drink the water straight from the taps and it's delicious.
After we returned from a week-long vacation (stagnant water), we noticed a fishy smell in our hot water side only. It's quite strong. I changed filter cartridges and shocked the system with some bleach, and this alleviated the problem... temporarily. 2.5 weeks later and the smell is back and it's driving us nuts. A few more details that may help:
- We have an indirect hot water tank (NTI V-series) so there is no anode rod since it's a stainless steel core
- There are only 2 of us in the household, so we don't use a ton of hot water
- I am unable to turn our domestic hot water above 140 deg. directly due to liability limitations from the manufacturer. There is a once-weekly "sanitize" setting that temporarily raises the temp to clean the tank, but this hasn't solved the problem. I *may* be able to set up the DHW as another heating zone on our boiler to keep it above 140, however.
Obviously, repeatedly shocking the system every few weeks isn't sustainable in the long run. Has anyone experienced something like this? Does anyone have any ideas on causes/solutions? Obviously, there's some bacterial or algae growth in the tank causing the issue... but how to remedy???
Thank you in advance for any suggestions/advice!
ETA: Prior to the new build and filtration system, water was pumped from the lake directly to a seasonal cottage/lakehouse with no filtration whatsoever. In 45+ years, there was never a fishy smell on either the hot or cold water sides, even though the water would go several weeks (sometimes) without use.