So I broke out the meter and tested the tap water.

FC- .17
TC- .96

My tap water needs a shock... hehe. THIS is why my water turns green at about 4" upon filling and we always have to shock new water. So there! Hrumpf!

Got interrupted by kids arriving home or I'd have ph and alkalinity to report as well. Will edit when I get a chance.

I got the bug to do this test because:
1) I have the equipment (Hannah Meter - tests under 1ppm) and,
2) Recent arial views of the uncovered reservoirs that got peed in and then drained on the news showed GREEN water.

Oh, we drink this stuff happily btw. Algae won't kill ya, apparently it's perfectly fine to drink it. The water is soooooo good btw. Even better than bottled.

Some drinking water supplies use monochloramine (CC) for disinfection, instead of chlorine, so your water might not be so bad as all that.

Oh... ok. Yes, that's it. So... how does that work in favor of less algae'd water? See below, from the water bureau's website.



Testing & Sampling Portland's Water
The Portland Water Bureau treats Portland's water with chloramination. This process starts with chlorine to disinfect the water. Next the city adds ammonia to ensure that disinfection remains adequate throughout our distribution system. New federal regulations are being developed and may require additional treatment processes by 2013.

The Portland Water Bureau also adds sodium hydroxide to increase the pH of the water to reduce corrosion of plumbing systems. This treatment helps control lead and copper levels at customers' taps should these metals be present in the customers' home plumbing.

Portland's water is currently not filtered. The Bull Run source meets the filtration avoidance criteria of the 1989 Surface Water Treatment Rule and has had a waiver from the requirement to filter since 1991.

The 1 ppm CC level is typical for chloramination and is monochloramine. That level will often inhibit algae growth, but the reservoir water you refer to wouldn't be chloraminated -- that process is done just prior to distribution in the piping from the water treatment plant to your house. Reservoir water is just water without chlorine nor monochloramine. So ammonia in from urine in non-chlorinated water would be akin to algae food -- a very nice source of nitrogen.

And you get a full serving of vegetables with your morning coffee.

Chemgeek, I know from aquarium keeping that more and more municipalities are adding chloramine to tap water instead of chlorine. I wonder if TFP ought to insert some information about that into stickies and Pool School. Filling your pool with chloramine ought to require slightly different responses, right?

Not really. You still add chlorine to the pool to get rid of whatever chlorine demand there might be in the fill water. In the case of 1 ppm CC, it will not take more than 1 ppm FC to get rid of it (remember that the 10x rule is wrong and only applies to the amount of needed chlorine to oxidize ammonia, not monochloramine). So having a normal chlorine level upon fill is usually sufficient though a shock level makes the conversion go faster. With an FC that is around 10% of the CYA level, you get rid of around 90% of the CC after 4 hours and you get rid of around 99% of the CC after 8-9 hours -- that's at 77ºF and it would go away faster at warmer pool temperatures.

Thanks, as always chemgeek. I just love having smart friends.