Help..tank whacked!

[Hiame70]

Hi, I posted a question awhile ago about my algae problem. I had a blue-green alg. prob. and was doing 20% water ch. every 2 weeks. I was using R/O water from the grocery store because I had thought my tap was too hard. Well, I was told that my nitrates were too low (they were at 0) and that it wasn't necessary to use the R/O water, and also to increase my changes.
I added another DIY bottle of CO2, I have been doing 25% water ch. EVERY week, w/tap water. The blue-green algae isn't a prob. anymore, but what got worse was there's "green slime" alg. every where! And some of my plants are losing alot of leaves. The nitrates are still at 0, and a few fish have died recently. (I've had those fish 4 years, no prob.)
What am I doing wrong here? :confused:

[djlen]

You really need to give us more info on your tank....pH,gH of your water,kH, and whether you are fertilizing the plants. From what you're saying, it sounds like you need to dose KNO3(nitrates), but give us more to go on. The object is to find a balance between ferts., CO2 etc.
Len

[Hiame70]

Oh, I forgot.....
Nitrates @ 0
GH @14
KH @19
the hardness definatly went up! The GH & KH used to be at about 8-9 when I was using R/O water....
no ammonia or nitrites....
I use Flourish Excel

[tyler]

how sudden was the change in hardness?

[plantbrain]

Muummm dead fish, not good.

Since your NO3 are 0 there's a good chance there's none in your tap water.

Do a 50% weekly water change. You have already changed over to this GH/KH combo so it's not likely any harm will come due to this. What species of fish?
Also, how big is the tank?

Flourish excel if overdosed will kill fish. Don't use this unless you have a low light tank, use CO2 gas. Measure the pH and see what the CO2 content is with the pH/KH/CO2 table. Try to get 20-30ppm for your KH, it'll be around 7.1-7.3 or so using only CO2 gas to get it to that pH.

I add about 1/4 teaspoon per 20 gallons of tank every 3 days with high light/CO2 fully planted. It's unlikely you'd need more than this amount. This dosage adds about 10-11ppm of NO3 every dose. For a 20 gallon, adding 5 mls of traces, a bit of KH2PO4, a couple of rice grain's worth every three days also works well if the tank is fully planted and has good CO2.
Weekly 50% water change, Add dechlorinator and K2SO4 1/4 teaspoon per 20 gallons after the water change and the other three items every 3 days or 2x a week or so. Scale up/down to suit your tank size.

Regards,
Tom Barr

[Hiame70]

Thanks for the great replies. Very helpful. The tank is a 40 Long.
Whenever I try to test my pH it's off the chart (dark, dark blue) the kit came with, so I'm assuming it 8.0 or over.
I have had recommendations to use ppm before, but don't know what it is! How can I get/make some?
thanks ;)

[plantbrain]

ppm= parts per million,
mg/l= milligrams per liter and
mg/l also = ppm.

You want a certain level of CO2 in the tank. By measuring the pH and the KH(which stays put and doesn't vary too much generally) you can figure out the CO2 level in your tank.

pH is the one that will move around due to the plants sucking up the CO2 out of the water.
You can print this little table out and use for quick ref's.

http://www.sfbaaps.com/reference/table_01.shtml

You'll follow the table's KH on the verticle scale/up/down that you measured already at 19KH(check this again in case) so you follow that row across till you find 30-20ppm approximately. So in your case, you need to add enough CO2 to get the pH down to 7.3-7.4 or so. 7.1 is a bit off and a tad too rich in CO2, 7.2 would be the max lowest pH you'd want.

A good narrow range test kit is essential for good CO2 as you can see, only a movement of .1 to .2 pH units will cause the level CO2 to vary greatly.

40 gallons is getting to the upper range for using DIY especially if you have a lot of light.
You may need to add more CO2 gas. Excel will only work for low CO2 needs/low light and over dosing will kill fish.

Regards,
Tom Barr