1 Gal. Calcium, Lime and Rust Remover

I have left it on much longer before (in toilet). It was diluted , but worked great.

You should not use CL on glazed ceramic tile. It can remove and/or dull the tile and also cause changes to the grout. Use a vinegar and water mixture and soft bristle brush if necessary.

Well, while it would remove deposits ?, It would also likely remove the finish from your pool tile. Furthermore, contact with chlorinated water will release chlorine fumes which are deadly. The simple answer is no, do not use it in your pool.

Thank you for your inquiry. The Zep Calcium, Lime & Rust Remover contains a very strong acid. It is not advisable to use in a spray bottle. Fill a plastic bucket with the Zep Calcium, Lime & Rust Stain Remover and warm water, and apply the mixture with a brush or sponge. Allow the mixture to penetrate stain for 5-10 minutes, then rinse surface thoroughly with water. I hope this information is of help. Should you have further questions, feel free to contact us at 1-888-805-4357. We appreciate your business and look forward to serving you in the future. - Zep Inc.

No it is not good to mix these two chemicals together. Makes a caustic vapor

Hello, Mhbar! No, it is not advisable to use on natural stone as etching may occur. However, you may use the Zep Calcium , Lime & Rust Stain Remover on other hard surfaces such as porcelain tubs, sinks, toilets, brick , cement, stucco, glass and fiberglass.I hope this information is of help. Should you have further questions, feel free to contact us at 1-888-805-4357. We appreciate your business and look forward to serving you in the future. -Zep Inc.

Does not work well on build-up however, it is a very good general purpose cleaner.

Although I haven't tried I can't see why not. If I use it on tile that has grout in between, the grout would be much more porous than anything inside a washing machine. If you have calcium lime or rust build-up it sounds like a fantastic idea. I don't think I would use it all the time as it may dry up any of these silicone rubber fittings but I can see why an occasional use wouldn't be advantageous.

Yes, it is safe. I have used it on plumbing systems 40 years old. Use as directed and rinse well.

The most simple answer is No, CLR is not safe for use with metal. You can try it but make sure you rinse thoroughly. A better answer for hot water heater is to drain sediment regularly and replace the cathode tube as needed.