Originally Posted by tecwzrd
Hundreds of users here have used the shrimp method without fouling the tank.
Count me as one of those hundreds... and I even "fouled" my tank and lived to tell about it!
I used one shrimp to cycle a 10g quarantine tank. Oops. Didn't realize what I'd done until my ammonia got up to about 6ppm and I wasn't seeing any increase in nitrites. No biggie - I just took the shrimp out and did a 50% water change, and after a couple days the nitrites started showing up. Everything cycled fine, and I've had two fish through it that can attest that it didn't "mess up" the tank.
Only issue I had is that my shrimp had been frozen and probably treated with something. My phosphates in my QT were really high after my cycle. But after the cycle was done, I just did several 50% water changes over the course of a couple days and threw in a Rowa phosphate sponge and things were OK.
As mentioned earlier, hyposalinity has NOTHING to do with cycling. It has to do with treating parasites. Cycling only deals with getting an ammonia source so your bacteria can build up to get rid of that ammonia. Whether it's fish poop, fish food, or a dead shrimp, it doesn't matter.
Go with the shrimp and find a new person to talk to at that fish store!