The Consequences of Shading

Observations and Actions

1. Water is noticeably clearer but still has a greenish tint. The algae problem must be clearing up. I've been keeping the front of the tank covered with my whiteboard during the day. I also created a roman shade for only one of the windows, which also helped with he sun as well as decrease the heat in the room. I also have been limiting the feeding to 1-2 times per day; not just when the goldfish are clamoring for a meal.
2. My water readings are changing again. For the first time in awhile, the pH has gone below 6.5. The water hardness has gone up but the carbonate hardness has gone down. There are zero nitrites, but an increased level of nitrates. Are the plants not making use of the nitrates? The water temperature continues to be steady.
3. The snail died. I'm guessing that it may have had to do with the change in pH.
4. I topped off the tank with some naturally dechlorinated tap water (I left it uncovered, in a bucket, for a couple of days). I then added 40 drops of pH UP to the tank to get the numbers up. I should have added less for less of a shock. I know that the goldfish will handle it, but I'm not sure about the catfish. Both appear to be very healthy and active.
5. The plants are not doing well. This could be due to the pH changes. The fostered plants have brown spots on the leaves and appear to be wilting. Their health was floundering before I put up the window shade, but the decreased sunlight is a factor. The fostered plants have actually pointed to the left; towards the light of the closest, eastern-facing window. I am going to have to purchase a grow light but I don't want to spend the money.

Analysis

Regarding the algae v. plant light conundrum, I'm going to have to either move the tank or buy a grow light. While the sunlight is great for the plants, it's not direct. The room shading, which helps limit the algae growth and makes the room more comfortable in the summer, limits the plants' growth. I need to bite the proverbial, financial bullet and buy a grow light. If you have any recommendations, please provide a comment in the page or send me a tweet (@the1verse).

The pH dropped to 6.0. I'm very concerned about this since I really didn't do anything to the water. I'll have to read more about why this happened, but my observations tell me that the shading is the only external change. I don't recall anything else being done.

The Numbers

Date	GH General Hardness	KH Carbonate Hardness	pH	NO2 Nitrites	NO3 Nitrates	NH3/NH4 Ammonia	Temp °C
6-Jun	180	40	6.0	0	160	0.00	24°