Tap Water Levels

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Aquarium Advice Apprentice
May 8, 2023
Sheffield, UK
I have started a new tank and i am ready to start the process of cycling.

My tank is fully setup with working filter, heater and lights but i have only put in gravel and a few large pebbles so far, i didnt want to put live plants in incase my water was not suitable.

My tap water is testing 0 on gh and kh and low for ph (i would say below 6.4), i am currently using testing strips as i didnt have the funds for the api master kit straight away.

After reading lots of articles i have come to the conclusion that my water is in no way suitable for fish or plants currently but i am at a loss on the next steps to take. I have read that introducing crushed coral will increase water hardness and ph but if there is none in my water supply how do i maintain the parameters long term?
Contact your water supplier. They can confirm your water parameters. You mention you are UK based in your intro post, you should be able to go onto your water suppliers website and get a water report for your area.

The test strips are essentially useless. They may be correct, they may be off completely. You simply cant trust them unless you have a more accurate test to compare them against.

If money is tight then test strips are not the way to go. Those 5 in 1/ 6 in 1 test strips dont include ammonia, so you need to buy 2 different packs of test strips. Those together are almost the cost of a master test kit. You only get 25 tests from each pack of test strips, whereas a master test kit gives you 100s. You are cycling your tank, so you will testing daily for maybe 3 months. So test strips will set you back about £120, whereas a £50 master test kit will see you through cycling and still be going for a year or two. The master test kit is 100% the more cost effective option.
I have a master kit on order now, my tank setup came with both lots of testing strips as well as dechlorinator and microbe stuff (unused lol)
If your water is soft and acidic (0 GH, 6.4 pH) then you can keep lots of fishes and plants. Most aquarium plants are fine in soft water with a slightly acidic pH.

Lots of fishes from South America (upper Amazon) and from tropical Asia naturally occur in soft acidic water. Most tetras, angelfish, discus, gouramis, Bettas, Corydoras and rasboras come from these areas and love soft water with a low pH.

If you want fishes from harder water (livebearers, goldfish, rainbowfish, African Rift Lake cichlids), you can buy a Rift Lake water conditioner and add that at a lower dose rate to raise the pH, GH & KH. You would have to use that every time you did a water change and the water should be made up at least 24 hours before it's used.
Thanks Colin,

I plan to keep some neon tetras, platys and some corydoras, as well as some live plants once the tank is cycled.

Im just waiting for my ammonia and master test kit to arrive now so i can start the cycling process. I would attach a pic of what it looks like at the minute but i can't work out how lol.
Platies, swordtails, mollies and guppies need harder water with a GH around 200ppm (250ppm+ for mollies) and a pH above 7.0. If you want these fish, get a second tank and add some Rift Lake water conditioner.

Neon tetras and Corydoras will be fine in your water as it is.
So i finally have my master test kit and my ammonia.

Is it normal for the ph of my water to have risen in the 6 days that it has been sat? Originally with the test strip it was showing bright yellow which was below 6.4, just taken starter readings to begin cycling the tank and it is now 7.6 (both test strip and api kit).

Filter has been running and heater has been set on 24, i haven't had the light on.
Tap water is high in disolved CO2. Disolved CO2 forms carbonic acid in the water and lowers the pH. Once the water leaves the tap CO2 will offgas and the pH will rise. So dont test your tap water straight out of the tap, let it sit in a container overnight before you test the pH. This will give a true test of the pH of your tap water.

You could also have substrate or rocks that will slowly dissolve in your tank. These could be calcium carbonate which will raise the waters pH.

Natural processes will also alter the pH in your tank. For example fish respiration will acidify water, plant respiration will do the opposite. The nitrogen cycle will also lower pH.

This all combines to the pH of the water setting out to a point that will be different to what it comes out of the tap. As you cycle the tank and add fish etc you could find things fluctuate further.
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