Co2 Confusion And Test Kit

OK so I've read up a lot about CO2, and plant and cycles. But for some reason my head is still mashed.
I have a 75 litre tank and it's gone through its cycle, after been replanted etc. It also has 3 fantails about 3-4 inches including their tails.
What I'm still not understanding is my water tests and if my co2 it 2 much or two little in the tank.. I love my fish and a love having real pants and I want them both to do well.
So I've not done a water change for 6 days and this is test strip readings I have..
Ammonia = 0 : Nitrite = 0 : Nitrate = 50 : GH = 250 : KH = 50 : PH 6.6
Co2 is 1 bubble ever 2 seconds and I run an air stone at night...
Do these reading look right?
I'm still very confused
I've added a picture of my tank for a reference.
I hope someone can help with my confusion
Lucy

 

Do you know what your degassed pH is (Put some tap water in a jar and let it sit for 24hrs and then test the pH)? It would be worth investing in a pH pen that you can calibrate and use to test your pH.
You need a baseline pH to give you an idea of how much CO2 you are adding to the tank, the more CO2 you add the further your pH will drop. You should shoot for around a 1.0 drop in pH.

 

Thanks for your reply, that's been really helpful, I don't know what my de gassed PH is from the tap I shall do that, should I do it to my tank also as I run my air stones at night to reduce co2 whilst my plants are in the dark .

 

1 bubble every 2 seconds doesn't sound like its enough. I would start at 2 or 3 bubbles every second.

 

You only need to test the pH of the tank as you're injecting CO2. Use the baseline number you got from your degassed tap water to compare it to. Remember regardless of pH or any other CO2 test your fish will tell you if there is too much, watch them and if they start acting stressed/swimming at the top back your CO2 off a bit.

 

Thanks, my fish are swimming about well and my blue Oranda live 3/4 to the top of the tank all the time. He always has.. But there's no gulping and they seem happy . Do those co2 chart things work ph kh = co2 charts

 

the pH/kH charts can be used as a general reference but they are far from perfect

 

I use a drop checker with a 4Kh solution. If it's a nice green color you are around 30ppm. Blue, low CO2, yellow and it's getting too high. It's a pretty small tank, 1 bbs may be enough.
I can get 30ppm in my 54g tank with just 3bbs. It also depends on if you use a reactor or stone to inject the co2. My reactor is nearly 100% absorbion. A diffussor will have a lot of waste.
Also, how are you measuring 50ppm Nitrates? Most kits do 20/40/80. If it's right, it's a little high, I think you generally want closer to 20-30.

 

A drop checker is the best option, the charts aren't always very accurate.