Scary Gh Levels

[fishleg]

First time I have ever tested the GH levels but the solution took 24 drops before turning blue which comes out as a scary 24 * 20 = 480ppm. PH is around 6.6 - 6.7 KH is about 3.5 - 4.0. My tap waters GH is around 4 - 5 80-100ppm so I must be doing something extremely wrong or its built up over many years.

I've owned the tank for many years without really any major problems. Tank is 20 gallons with around 4 fish, 2 Shubs, 1 Plec, some shrimp, few snails. I must admit I have no idea what a high GH means.

I normally replace around 10% of the water every 1-2 weeks. I use one of those external fluval filters.

What affect will it have on the plants and fish in my tank ? and what causes so high GH levels ?

Could not replacing the carbon in the filter as much cause this to happen as I often leave it for around 3 months before changing it as I've alwasy been confused if the carbon would just take away any fertilizers I add for the plants.

 

[RadaR]

If the GH in your tap water is 4 - 5 80-100ppm then something is obviosuly raising it in the aquarium to get to the 24 * 20 = 480ppm. This may be rocks, gravel that are leaching calcium and/or magnesium into the water. What decor do you have in there?
A high GH level may cause SOME plants to not grow properly. Personally I havn't had any problems as of yet.
You shouldn't have carbon in planted tanks. Take it out and leave it out.

 

[fishleg]

I added some cuttlebone to the tank about a month ago mainly for the snails in the tank so their shells don't fall to bits. I'm talking about a 2 by 2 inch piece, surely that cant be the cause ?

In terms of stones I've got some stones from the beach years ago but on top of those I've added a layer of aquarium fine sand and then on top of those some pet shop pebbles. I'm no expert with stones though what should I be looking for ?

Another thing I often leave the wool around the plants I buy then bury them under the sand, could it be the wool some how >< ?

Would it be sensible to replace 50% of the water over 7 days just so its within the normal range ?

 

[jesseoneill]

It's the cuttlebone. A 2x2 inch piece, chemically speaking, is huge (especially in a 20 gallon tank). Cuttlebone, as you know, is mostly calcium carbonate, and calcium carbonate is the principal cause of hard water. I did something similar to my own tank with two small rocks that I didn't realize were selenite (in other words, gypsum or calcium sulfate). After just a couple days things clicked in my head and I recognized what the rocks were, but in that short time my tank's hardness had already jumped about 15 degrees.

 

[fishleg]

*quickly rips out the cuttlebone*

Thx Jesse, Ill keep doing 10 - 20% water change for the next 2 days then ill test it again would that be ok ? I dont wanna shock the fish too much.

 

[jesseoneill]

That should be fine. Neither my fish nor my plants experienced any visible signs of shock, but since I keep Apistos (which like soft water) I did a few 20% water changes every other day with pure RO water to bring GH down.