You also need to meet the lenders DSCR.CFBT = Income - Expense - Debt  and Cash-Cash = CFBT/Down - You have XLS and easy to figure out.Another way to do quick check is some sort of acid test = (Expenses+Debt)/Income. 

After the guy did some cracks fixing and acid wash (I wasn't there to watch them do it), some portion of the pool wall turned yellow after filling with water.

I found a 3 bedroom 2 bath for $10,000 and I'm going in the morning text we do the due diligence and I'm thinking it's only going to need about 15,000 if that in repairs.. the acid after market value should be anywhere between 75,000 and 100,000..

Sooner or later the CFPB is going to send you a CID.

Also muriatic acid might work but Ive never used it.

Inventory turn over, or an acid test or ROI are particular to industries as a basis to judge performance of one activity.

but one is an acid and the other is a base that neutralizes the smell completely. 

If the repair isn't completed then we bill them for the service call $75 as per the lease. we have some owners that provide the filters which really helps and certainly not a big maintenance expense compared to and AC acid bath. 

I've also found the forums on citydata.com to be helpful and combined with street view can give a good indication of what a neighborhood is like but for me the acid test is would my mom feel safe walking around?

If you are on a well or spring you might want to use CPVC because acidic water will eventually wear out the crimped fittings.