Black marks on pool steps

[hoberney]

Thanks for the quick reply!

I do have my own test kit and test the water myself. I am using the ColorQ Pro 7 plus test kit. The measurements I posted are from using it. From the research that I did the feedback seemed to be pretty good on the ColorQ test kit as far as accuracy so I went with it.

I will take a picture and send it in to see if that helps identify the problem.

I will also complete the pool chart form as well.

Thanks!

Alan

[Watermom]

That's a pretty expensive kit and you're right it did get pretty good reviews. (I wasn't familiar with it, so I looked it up.) The downside to it, though, is that it is a DPD kit and will not test high chlorine readings like the K-2006 will. Also, from what I could tell, there is not a CC (combined chlorine) test with that one which is also an important piece of information to have when you are fighting algae problems. Some reviews also suggested that the CYA test gives low readings and the calcium hardness test is not too accurate. Maybe ChemGeek or Waterbear will have information on this kit that they can share.

Hopefully, someone can help you figure out what those black marks are. Glad to have you here on the forum with us!

[PoolDoc]

Never heard of anything like that. I'll see if Waste or Waterbear have.

[waterbear]

I'd like to see a pic. Also, be aware that the magic eraser is a actually an abrasive pad and can damage the gel coat on your pool and make matters worse. Black stains are usually either copper or mangansese or an algae. Start with a full set of water test results done with your ColorQ (which, btw, while good, does have some limiitations compared to the the LaMotte 7022 FAS-DPD test or a Taylor K-2006)