The Happy Camper products also have and "Extreme Cleaner". The extreme is just for cleaning up scummed up tanks. In the case of the grey tank, you will the tank with water about 3/4 full. Mix up the cleaner in some water to disollove it, then pour down the shower or sink drain. Then keep filling the gray tank by the same faucet you poured the cleaner mix down.
Once water starts backing up in the shower drain, stop filling. It's 100% full.
Then wait 8 to 24 hours. This cleans the scum off the top of the tank, pipes and all. Then drain the tank. I bought a small container of the extreme cleaner to de scum my gray tank top after we bought the camper (used)
After the extreme clean the key is to keep the tanks clean. I installed a tank sprayer in both the gray and black tanks to keep them flushed of build up and use the enzyme/bacteria type of tank products. We are now back to Happy Camper regular tank treatment. We have used Zea-Zyme which works good too. We use it in both the gray and blank tanks.
I have never had a black or gray tank senor problem since we started in 2003.
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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