The 10000K MH bulbs haven't arrived yet but I do have another tank with 250w 14000k MH lighting and it out preforms my other t5 6500K and 10000K+ tanks in all respects as long as you can balance the ferts and pump in heaps of co2
I recently purchased these bulbs to fit 2 commercial 150w units that I got from Ryan
http://cgi.ebay.com/MARINE-COLOR-HQI-150W-10K-10000K-METAL-HALIDE-BULB-/160578863363?pt=LH_DefaultDomain_0&hash=item25633f0103
Undulatus comes from the word undulate meaning to have a wavelike appearance or form
So many plants with wavy edge leaves are given this name.
Eg
microsorum pteropus undulata
anubias undulata
hosta undulata
Cryptocoryne Undulatus
Aponogeton Undulatus
Perhaps I should look after it for you Jen.
Especially now that you are looking after rescued fish, have recently had a promotion and are no doubt preparing for the conference
As nitrates rise, the PH in a tank with unbuffered water rises
So the PH of your tank will gradually build up all week and then crash when you do a water change.
So it's more a matter of PH swings and crashes rather than spikes
The easiest and cheapest way to get high quality soft water for your fish is to collect rain water.
just run one of the down pipes from your roof into a 200L drum.
Have your fish shown any signs of stress caused by this 2 deg temperature variance ?
If not.... Why worry.
My tanks drop way more than that every week when I do cold water changes. If anything the fish love it.
It even stimulates many species to breed.