Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: mizuti on June 10, 2017, 08:00:46 AM

Title: Soft water *update*
Post by: mizuti on June 10, 2017, 08:00:46 AM
Hi all, very new to fishkeeping - infact I haven't even started cycling yet but I'm getting there slowly! I've been advised on another post to check the hardness of my water before selecting fish, which is fine I obviously want fish that can thrive in the conditions I can readily provide. I haven't tested my own water yet, waiting for the test kits to arrive but going off my water company information I have soft water, it says
Total hardness average 35 mg CA/l
Hardness Clark 6.125
pH 7.3 average
Does soft water affect cycling? How will I know if fish are adversely affected?
Title: Re: Soft water
Post by: Sue on June 10, 2017, 10:09:34 AM
There are about half a dozen units for hardness, but fish profiles use just two. Your units are not used in fish profiles, but they can be converted. When you look up fish that take your fancy, their preferred hardness range will be given as either German degrees (also called just degrees or dH) or ppm (which is also called mg/l CaCO3)

Your water hardness converts to 4.9 dH and 87.5 ppm.

These are the two figures you need when looking up fish. Some sites use one, some use the other. The best site for looking up fish is Seriously Fish.




As for cycling:
In fishkeeping we use two hardness terms, GH and KH.
GH is general hardness and is the numbers on your water company's website that I converted above.
KH is the amount of carbonate and bicarbonate in the water. The K comes from the German for carbonate. Occasionally, a water company lists KH as well as GH but they call it alkalinity.

The bacteria we want to grow need inorganic carbon, as in carbonate, and trace minerals to grow properly. As a rule of thumb, KH is high with GH or low with GH. As your GH is low, it is very likely your KH will also be low. Since you are waiting for your testers to arrive, you'll be able to confirm just how low KH is. If it is below 4 degrees, you will need to artificially boost carbonate during cycling. You should be able to get away with the trace minerals with GH 5 degrees, but if you intend growing live plants, you may as well get some liquid fertiliser now and add some of that. The best one is Seachem Flourish, the one with nothing else in the name. It contains most of the trace element plants need. You won't need to use as much as the dosage rate says because you just want to add a bit more trace elements not feed a tank full of hungry plants.

The other problem with low KH is that there is a danger of a pH crash. We add ammonia to cycle the tank and it is converted to nitrite and then nitrate, both of which are acidic - they lower the pH. Carbonate reacts with acids and stops the pH falling. It buffers the pH. But when there is not much of it, it gets used up leaving nothing to buffer the pH, so the pH falls, and it falls quickly. The bacteria we want to grow don't like low pH. They stop multiplying around pH 6.5 and become dormant at below 6.
The way to stop a pH crash with low KH is by artificially boosting KH.

Once the test kit arrives, can you post the KH reading, please. If it is at or below the safe limit, I can tell you what you need to do.




I have done two fishless cycles, one with the old method and one with the newer method written up on here. My GH is 5 dH and my KH is 3. During the first fishless cycle, my pH dropped off the bottom of the scale so when I did the second I boosted KH when I set the tank up and the pH remained stable.

Title: Re: Soft water
Post by: Sue on June 10, 2017, 10:18:52 AM
I forgot to mention fish.

As long as you choose fish that like soft water, they will be fine in your water. If you do need to boost the KH, it will be removed by the big water change at the end of the cycle.

Fish profiles say this fish needs this hardness range and this pH range. Fish can cope with a pH outside their preferred range better than they can cope with a hardness outside their preferred range. As long as the pH is not hugely outside the preferred range, fish that like your hardness will be fine.
You need to look at south American, most Asian, and most African river fish. That gives you an enormous choice.
Avoid central American fish (including livebearers) and African Rift Lake fish.
Title: Re: Soft water
Post by: fcmf on June 10, 2017, 11:17:24 AM
Excellent advice from Sue.

Once you're past the cycling stage, and choose fish suitable for your water, you ought to be fine. If this is of any reassurance, my water is softer than yours - looking at the latest figures, 1.91 Clark, 1.52 German, 8.75 mg Ca/l or 27.18 mg/l CaCO3 or ppm - and, aside from a couple of small pieces of limestone/Tufa rock in the tank, my harlequin rasboras (now 2+ years old) and x-ray tetras (now 2.5+years old) have been faring fine in that so far (touchwood!).
Title: Re: Soft water
Post by: mizuti on June 10, 2017, 04:50:07 PM
Wow thanks so much for that wealth of information! Harlequin rasboras are one of the fish I was hoping to get too, so that's good.i will post the results of the test when it arrives. Thanks again.
Title: Re: Soft water
Post by: mizuti on June 28, 2017, 06:52:58 AM
Been a busy week so only getting to post now, sorry for the bad quality picture I don't know how else to get it a file size which is small enough to upload. I'm set up and started the fishless cycle 6 days ago, no change in my ammonia level yet. The orangey brown one is the GH and the green one is the kh. My ph seems fine when I measure it with the liquid test kit, but reads lower on this test strip so I don't know how accurate they are. No sign of my cycle starting yet but I'm patient! Just read (on this forum) that when the cycle is complete I will need to put most of my fish in at once and not gradually, since I've only definately settled on some corys I have some more planning to do.
Title: Re: Soft water
Post by: Sue on June 28, 2017, 09:34:58 AM
I have not used those test strips so I'm not familiar with the colours and what they mean.
What number does the strip give for KH?

You don't have to add all your fish at once as soon as the cycle finishes. It's just that most people can't wait a day longer than necessary  ;D It will be a few weeks before the cycle finishes - my last one took 7 weeks. If you don't have a final list by then, just get the species you know you want. The bacteria will be fine for a couple of weeks, but if it is longer than that before getting more fish, add them a few at a time with a week between additions.

The bacteria don't die within hours if they are not fed as used to be thought; they are fine for at least a couple of weeks, then they start to go dormant before finally dying months later. But the longer they are dormant, the longer it takes them to 'wake up' so there can be a time lag during which ammonia can build up if too many fish are added in one go.
Title: Re: Soft water
Post by: mizuti on June 28, 2017, 11:24:48 AM
I think it's GH between 4 and 8 degrees, and kh 3 degrees. I have the king brand strips too. I think I've decided on around 8 Cory's, 10 dwarf rainbow fish and a couple of honey gouramis.
Title: Re: Soft water
Post by: Sue on June 28, 2017, 11:55:41 AM
I also have KH of 3 and suffered a pH crash during my first fishless cycle. Keep a close eye on your pH. I know the method does not mention testing pH, but I would do one every time you test for ammonia and nitrite.


The way to stop the pH crashing during cycling is by adding bicarbonate of soda, the same bicarb that you buy in small tubs from the home baking section in the supermarket. You may already have some.
For my second fishless cycle I used 1 x 5ml spoonful (level spoonful) in 25 litres and didn't need to add any more during cycling. So for 125 litres, use 5 x level 5ml spoons.
This will increase KH and pH but it won't change GH as bicarb contains only sodium which isn't included in the GH test.

At the end of the cycle, you will need to empty as much water as possible before getting fish to remove all the nitrate the cycle makes and this will also remove all the bicarb.



That sounds like a nice combination of fish, though the rainbows might be a bit hyperactive for gouramis' liking. I suggest leaving the gouramis till last and see how active the rainbows are first. Adding a couple of fish a few weeks later won't overload the filter. Then if you think the rainbows might be a bit too active, you can look for an alternative that would be OK with them.
[For example, peacock gobies/gudgeons, Tateurndina ocellicauda would work well. I have some of those  :) ]
Title: Re: Soft water
Post by: Sue on June 28, 2017, 02:54:49 PM
Just to add, in case you haven't added any bicarb yet - take a bit of water out of the tank and dissolve the bicarb in that then pour it back into the tank. if you add the powder straight to the tank it'll sit there for ages in blobs till it dissolves.
Title: Re: Soft water
Post by: fcmf on June 28, 2017, 07:44:12 PM
My ph seems fine when I measure it with the liquid test kit, but reads lower on this test strip so I don't know how accurate they are.
I find that the PH reads quite a bit lower on both Tetra and JBL test strips than liquid-based test kits and my water supplier's website would indicate. For KH and GH, it's the other way round ie the test strips read quite a bit higher.

It's a bit hard to tell what yours is reading ie the GH is probably as you say while the KH is a bit more difficult to work out. It's important to read the results in the specified time period as they change over time ie I've left the test strips lying on the table for ten minutes and it completely alters the readings. I've also ended up with colours that don't seem to match any of the colours eg my tap water KH is too low to match any of the colours.

Best of luck with the cycling and following Sue's excellent advice. It's all getting exciting now with making your definitive choice of fish - looking forward to reading what you finally opt for.  :fishy1:
Title: Re: Soft water
Post by: mizuti on June 29, 2017, 07:37:11 AM
Thanks for the advice, I will try to get another kh reading this morning, and I'll test my tap water too. Is low kh only a problem during cycling?

The peacock gobies are very nice. My lfs, well not exactly local but the nicest one in my area is huge so hopefully they would have some of those in if gouramis weren't doable.
Title: Re: Soft water
Post by: fcmf on June 29, 2017, 08:16:39 AM
Low KH can also be a problem after cycling, depending on how low it is. However, you might find this helpful for some suggestions for once the cycling process is over: https://forums.thinkfish.co.uk/new-fishkeepers/re-addressing-soft-water/msg27272/#msg27272

Title: Re: Soft water
Post by: Sue on June 29, 2017, 10:43:42 AM
I have been keeping fish for about 20 years. At first we had only dial up internet which I didn't use (the cost!) so I relied on out of date books in the library, most of which said water changes were bad. So I only did them once every 3 or 4 weeks. And of course they never mentioned testing the tank water.
I finally got a test kit after several years and one day tested the pH and discovered it was off the bottom of the scale. That led me to fish forums, and Thinkfish in its previous incarnation had an Advisor. He said that the most likely cause was low KH, and I found a hardness table on my water company's website which confirmed this.
The advisor's recommendation was to use remineralisation salts. These are mainly used by those fishkeepers who use 100% RO water. There are no fish in the hobby that can survive in pure water so some minerals must be added back. Adding these minerals to soft water makes it harder, they increase GH as well as KH. But I did not want to increase GH so I did not use any of these salts.


My tap water has GH 5 dH/90 ppm; KH 3 dH/54 ppm; pH 7.5 after gassing out. This is similar to yours.

So how do I prevent pH crashes if I don't use remineralisation salts or coral/limestone etc? Water changes. All I do is at least 30% water changes every week without fail.




* Gassing out. Has anyone mentioned this yet? Freshly run tap water has gasses dissolved in it which can change the pH. If we leave a glass of water to stand overnight, the gasses will come out and the pH will be different. It is useful to know the pH of both freshly run tap water and tap water that has stood overnight.
Title: Re: Soft water
Post by: mizuti on July 01, 2017, 06:23:03 PM
Thanks to you both. I plan to do weekly water changes of 25% anyway so I can make that 30 at no extra hassle really. Just tested my tank today and my ammonia has dropped almost imperceptibly and my nitrites are at 0.5, so at least I know the cycle is starting, happy days. im following the guide for fishless cycling in this forum.
I had heard about testing a glass of tapwater then testing the same glass in the morning I haven't done this yet though. Will keep an eye on the pH during cycling then hopefully the water changes will   keep the pH stable. I really don't want to be adding chemicals like pH+ as I think I'd be crap at maintaining a steady pH that way.
Feel like I'm one step closer to getting my fish woop!
Title: Re: Soft water
Post by: Sue on July 01, 2017, 07:08:59 PM
Adding bicarbonate of soda just during cycling won't cause any harm, then it is removed by the big water change at the end. If you do find your pH falling while cycling, I would think seriously about adding some then you won't need to do a water change till the cycle has completed.


I didn't use the salts the Advisor recommended as I didn't want to be tied in to adding chemicals at every water change, and I haven't had any problems with just water changes - as long as I do them regularly. It was not doing them weekly that caused the pH crash about 10 years ago.

Title: Re: Soft water
Post by: mizuti on July 01, 2017, 07:58:07 PM
I have some in my cupboard from when I made sticky toffee pudding last week! I think I will add some anyway, il double check my tap water against my tank and see if it's dropped, if it has, like you say it won't cause any harm. I plan to do a full water change at the end of the cycle anyway as I have lovely brown bogwood water at the moment.
Title: Re: Soft water
Post by: Matt on July 01, 2017, 11:27:53 PM
You may wish to start changing some water prior to an ammonia re-dose especially if you cycle is starting to take hold. This will allow more tannins to leach from the wood and should mean that you stand less chance of having Brown water when you get fish. Wood can leach tannins for white a long time.
Title: Re: Soft water
Post by: mizuti on July 02, 2017, 08:02:08 AM
I don't mind the brown water, I know it will build up again after the big water change, i just hope the fish don't mind it after coming from clear fish shop water  :)
Title: Re: Soft water *update*
Post by: mizuti on July 07, 2017, 05:38:10 PM
Today my ammonia is 0 after adding the second  3ppm dose, my nitrite has fallen from 5+ to between .25 and .50 over the last 2 days so I have added another 3ppm dose. My ph had fallen to around 6.4, so I added the bicarb and now it's reading 7.6 so much better. Hoping to go to the fish shop on Tuesday as it's a rare day my son is at nursery and I'm off work. Fingers crossed! Thanks for all your help and guidance so far.