What appears to be Major GH problems.

[Newman]

I would have asked this in the newbie forum, since i am a newb, but i feel i would get a better response here.

I have an API KH and GH test kit. i know how to correctly test for KH and get a good reading, but have a problem with the GH.
Either i dont understand how to test for this liquid test (i assumed it was the same exact method as testing for KH according to the instructions) or my tank's water literally has 590 ppm GH !(thats 33 degrees)

now i tested my tap, and found a GH of 483.3 ppm (something like 27 degrees) this is quite high, but i dont get why my tank GH is SO much higher than the tap that i use to refill it?
The tank is a 40 gallon, slightly planted, slightly alkaline (pH of 7.4-7.6) with a normal 8 degrees (140ppm) of KH levels. It contains few fish (the ones mentioned in my sig)

What is cauing such a high GH and how can i get it lower and maintain it at around 300ppm? is there a dangerously high concentration of calcium, magnesium, and other ions that contribute to GH levels?
Because levels of 500+ is borderline harmful from what ive read =/
Please i beg you, someone help me out.

 

[stoddern]

API usually includes scale cards for color comparison, on the back of those is the instructions for the test it belongs to, that is if your using a drop test and not a dip test.

 

[Newman]

I am perfectly aware of that because all the liquid tests i use are API.
I am guessing youve never tested for KH or GH with a liquid test before? because those tests dont use color comparison charts (which i think is bull)
In those two unique tests, i have to count the number of drops it takes for the sample of water to change color (blue to yellow for KH and orange to green for GH)

So am i counting the number of drops wrong? i start counting the very first drop of the test solution, until the very last drop that it needs to change to the appropriate color. By this method i usually count 7-8 dKH (or drops) which is perfect for my future livebearer tank, but I started at 38 dGH (or drops) 3 days ago. 38 dGH is a whopping 690ppm of all those calcium, magnesium and other ions. i read those levels inhibit proper fish repiration... in the past three days tho the GH has been dropping. 33 dGH two days ago, and 30dGH this morning.
My best hypothesis for this weird occurance is the past presence of real sea shells in the tank. those must have been the source of the ions and such high levels of GH. Now, i removed ALL of them when i began working on the tank 3 days ago. so thats the best ive comeup with...i REALLY hope the GH continues to decrease and gets to about 300ppm or lower, cuz i think thats ideal for the fish and the plants.

 

[thejava1]

You know, this tank of death you've got sounds like it should be cleaned out and gravel replaced... at least that's what I'd do.

How much money are you willing to spend? Gravel can contain a lot of nasty crap in it, just my opinion though. I'm using active carbon that's included in my filters and it seems to be helping with water hardness, though I'm hoping the driftwood (coming in) will helpmore. Still may want to give it a try (active carbon) since your readings are soo high. From what I understand goldfish are filthy creatures, so maybe the years of them contaminated the tank- again id basically start the tank anew.

 

[thejava1]

anyway to answer your question- i think its the gravel.

 

[Newman]

Yea, I also thought so. I didnt get a chance to fully wash it out because i had fish in it, but i replaced all of the gravel with Flourite. Hopefully next week i get better test results o_o

 

[Lotus]

The shells could have increased the GH, along with other rocks you might have.

Hopefully, now that you've taken out those shells and changed the gravel, it will drop with each water change. It won't drop on its own, by the way; only through water changes.

 

[Newman]

i do a weekly water change of about 1/4 or 1/3 depending on how much aged tap water i have stored. So i hope it will start to drop week from week.