pH: Definition and measurement units. pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic. Since pH can be affected by chemicals in the water, pH is an important indicator of water that is changing chemically.
sealing a cinder block wall. I just finished sealing the cinder block wall in our basement with Baer waterproofing paint. After the first coat I noticed little orange rust colored spots in one corner of the room. Nice fresh white coat of paint, little spots the size of peas on one wall.
You do need to seal the plaster otherwise the new paint won't stick as you point out. My first choice would be to wipe down and then paint with a coat of diluted emulsion as you suggest. You might want to try this on a section of the wall before doing the whole lot to see if you get a good finish.Dilute PVA will definitely seal the plaster and I can't think of an obvious reason why you shouldn't use the wood glue-but there may be differences in the formulation you need to look out for.ou might want to try this on a section of the wall before doing the whole lot to see if you get a good finish. Dilute PVA will definitely seal the plaster and I can't think of an obvious reason why you shouldn't use the wood glue-but there may be differences in the formulation you need to look out for.