Hi,

1. what would equate to a very diluted 7.6 color? is that considered
7.6?

I would try re-doing the test. Make sure there are no bubbles in the
drops
when add them to your water sample. Also, make sure your test tube is
clean,
and don't cover the end of the tube with your finger. Use the cap.

no bubbles, and I pre-wash the test tube prior to testing using the aquarium
water (put some aquarium water in the tube, cap it, shake it up, dump it out
in the drain, and then put the real testing sample in.)... I've done the
test many times... now that I think about it, I can always make the color
go darker by adding baking soda (then the test color becomes near what my
tap would be.. darker blue), so I'm pretty certain it's not exactly 7.6, and
probably lower...

the tap is high in pH (about 8 when fresh out of tap, after overnight
settling, it is about 7.8). since the KH is low, the current thought is
that the water dept adds something in the tap to keep the pH high.

2. can a pH drift from 7.0 to 7.6 in two days when you dont' do
anything?

Yes. It may mean the plants are stripping all the Co2 out of the water.
How
much light do you have over this tank?

wow. power of plants..

Tank is can be regarded "moderately low light". I have ~5400K 55W CF (37G)
with the metallic reflector, sitting on top of a glass hood (Versatop). I
guess glass hood cuts down on the transmission of the light by about 30% or
so.. so the plants are getting about 1Wpg or slightly more. the tank does
get some sunlight right before the sun sets, but I've been shading the
window recently to prevent the direct light from hitting the tank (algae
reduction effort). The room is quite bright even then, with ambient
indirect light during daylight hours. the tank is about 8 ft away from the
closest large window and is free-standing. (the room has lots of very large
windows)

As for the GH...it could be a fluke in the water supply, or it could be
something dissolving in your tank. Gravel, rocks, shells, etc.

hmm.. no shells that I know of unless lots of snails died without me knowing
and fish ate the meat and thus didn't pollute water.. I have noticed some
snail shells getting stuck in the filter intake that the fish obvoiusly ate
the contents.. but I clean out the mechanical filter every week, so unless
those few little ones add GH.. the gravel I use is supposed to be inert
(50% epoxy coated, the other 50% is natural)

If you're using Onyx sand or gravel for a substrate, it will definitely
raise
your GH.

No Onyx. I have few cups of Flourite in there (my failed attempt to
localize Flourite near the plant roots).. but that has been in there for
months before this GH increase. It must be the fluke in the tap water
supply...

linda



Leigh

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