Another pH thread

Hi,

Before I start I jsut wanted to say that I have read the pH threads in the water and health section and I still could not answer my question, apologies if the answer was in there and I missed it.

Basically my neighbour has asked me to have a look at her tank as fish has been dying. The tank has been running for about a year, it is very bare. There is only gravel(bought from a lfs so should not affect pH) three small fish and it's about 100L and the tank is well oxygenated.

Her pH is 8.0 and the water that she uses when doing water changes has a pH of 6.0. The temperature is 27 degrees Celsius. Unfortunately I do not have her other water parameters.

It should also be said that I use water from the same well and it does stabelize at 6.5-7.0 in three separate tanks.

I just can't understand what raises and keeps the pH at that high a level.

I'm getting almond leaves, bog wood and plants for her(no fish in awhile) but would like to know what could be the cause the pH rise.

Thanks in advance for any input!

Melander

As you may have noticed in reading over the various threads, there are lots of different reasons why a pH may be much higher than expected.

Some reasons are quite obvious; others are not so obvious. The explanations for the latter group of not so obvious reason does, without a doubt, get into some quite complex chemistry if you're hunting for an explanation..

Lowering pH effectively and safely is not as easy as raising pH effectively and safely (as a good generalisation).

Bogwood, peat filtering, or similar 'soft' approaches to lowering pH would be the best to recommend before advising using various acid mixes (a more aggresive harder approach) to lower pH.

Messing with pH without taking care can kill fish.

If the water out of the tap has a high pH, then that is that explained in an easy go.

If the water out of the tap is lowish, yet goes up in the tank then the first port of call is to look at the easy and obvious reasons:
temperature differences between measuring, and rocks/gravels/ornaments that may increase pH.

But if they can be ignored, then it gets more complex:
eg could be lack of buffering in the water; could be high ammonia; could be normal biological process (such as photosynthesis) that will raise pH considerably in soft-water or poorly buffered water.

They are a just a few examples......start by a process of elimination first: ie check the obvious things first. Don't venture into one of the more un-usual reasons looking for answers until the obvious ones are answered.

ian

Thank you for the quick reply and the advice!

I will try to eliminate any reason one step at a time but i suppose there could be several factor joining in on this.

I'm also going to get the reading of her other water parameters and we'll see what they are.

I know it does not say much in these instances but the tank looks clean and the remaining fish actually looks well. Perhaps the survivors have adapted to the conditions.

The only changes I have made to her setup so far is an added plant(there was none) and added some stones(I felt sorry for the fish as the tank was so bare) I have also done a couple of water changes. The next step is to get some bog wood and almond leaves but I will move slowly on this and add one thing at a time. I'm staying away from any synthetic uppers/downers(I have never used them myself) and I feel that the origin of the problem would still be there anyway.

I'll keep you posetd.

Melander

Finally...

My neighbour has been away for a few days so it took some time to get another look at the tank.

The new readings are as follows:

pH: 7.5-8.0 it seems to have gone down, perhaps since my water change.

Ammonia: 0

Nitrite: 0

Nitrate: 110, so this seems to be the villain.

I have found out that she was cleaning her filter in regular tap water which would have killed beneficial bacteria, would this not increase the level of Nitrite?

She also told me that when she is away another neighbour feeds the fish quite generously which could be another cause of the Nitrate spike. I also watcher her doing water changes and she empties the water from the top with a cup and never really get to the bottom where the filth is. She now got a hose and a bucket instead.

I did another water change on the day and instructed her to feed a little bit less, clean the filter in the tank water(in a bucket) and to vacuum the bottom of the tank while doing water changes.

Is there anything I have missed? I still don't understand how Nitrate changes the pH really but the most important thing is to get this right for her this time.

Melander

If your nitrate is that high, you're not doing enough water changes. Try doing 20% every day for a couple of weeks and you will see a huge drop.

looks like all your advice has been recieved, keep up the water changes like christy says for a few weeks to bring the nitrates down, well done on spotting this and teaching your friend how to do it, unfortunately some lfs's are only in for the sale and not the hobby but with people like yourself willing to take time out to show people how to do it right we'll be fine.. kudos to you.. i think ian hit the nail on the head with his advice, and you spotted it when you did your tests, that was one heck of a high level.. nice one christy

as above post....to reduce this high nitrate.

and reduced feeding ill help stop feeding into the nitrate sink.

For the record, on a few questions you asked Melander:
the washing the filters......in the normal process of nitrification, washing in tap water is highly likely to kill off the nitrifying bacteria and thus reduce or eliminate the ability to oxidise nitrite to nitrate: hence, yes, you would expect an increase in nitrites.
However, in the real world the whole nitrogen cycle is not linear....and there are ways and means of having zero ammonia and nitrite other than by nitrosofication and nitrification. Under certain anaeorobic conditions a system can oxidise ammonium, using nitrites, directly to nitrogen gas (that would reduce ammonium and nitrites).

If the washing did kill off the nitrifying bacteria, then the nitrates already produced by an accumulation of nitrates will still remain unless specifically removed.

Effect on pH....... for all intents and purposes, nitrate is a neutral salt. But, it is nitric acid (a strong acid)that is produced during nitrification. Under normal conditions of having a good amount of carbonate buffering (or other pH buffer or high alkalinity), the nitric acid will react to form nitrate and, thus, not have (in itself) much of an effect on pH. If, however, there is insufficient alkalinity then the nitric acid will reduce the pH.

Now...then it gets more complex....if we consider the effect of removing nitrite from the system.
When ammonia is oxidised in nitrosofication, the product is nitrous acid (a weak acid)...but if there is sufficient alkalinity then the nitrous acid will form nitrites. But, as nitrous acid is a weak acid, then nitrites are weak bases (and so would tend to increase pH).
In reality, though, if you are producing so much nitrites/nitrous acid in the tank to have a very noticeable effect on pH then there is a much more serious problem at hand than the pH.


ian

Hahahaha,jaysus Ian thats some read.....90% of it was total mumbo jumbo to me but 10% was very educational so fair play to yeh!!

haha,me encyclopedia hasn't some of them words!!

Ger the knob!!

ger310 wrote:

Hahahaha,jaysus Ian thats some read.....90% of it was total mumbo jumbo to me but 10% was very educational so fair play to yeh!!

haha,me encyclopedia hasn't some of them words!!

Ger the knob!!

well....if the questions are easy, then they get an easy answer......but if the question is complex (and complex questions were asked), then it is not easy to give an easy answer. Diagrams are much better....but I can't draw a diagram on the forum.

ian

Omg thank you all for the replies!

@Christy, on my way with the water changes, just don't want to make it a habit me changing the water in the neighbours tank everyday.

@Sheag, thanks, i do think anyone else on this forum would do the same. Being mad about fish as most of us are it's hard not to dive into any tank.

@Ian, thanks alot for all the information, I have to agree with ger310 that alot of the information is still beond me but I think I got the basics of what your saying which is all i need. How on earth have you learnt all of that, not only from fish keeping I presume?

Melander

Melander wrote:

Omg thank you all for the replies!

@Christy, on my way with the water changes, just don't want to make it a habit me changing the water in the neighbours tank everyday.

@Sheag, thanks, i do think anyone else on this forum would do the same. Being mad about fish as most of us are it's hard not to dive into any tank.

@Ian, thanks alot for all the information, I have to agree with ger310 that alot of the information is still beond me but I think I got the basics of what your saying which is all i need. How on earth have you learnt all of that, not only from fish keeping I presume?

Melander

@Melander...... a lot of water chemistry that us fish-keepers deal with is quite advanced stuff, and would go well beyond most university chemistry degrees if we look at the reality in a fish-tank.
Fish tank water chemistry is like a 6 inch nail.....if you try to hammering in with a melon (ie leaving cert chemistry or even standard university chemistry) then you leave a bit of mess in the melon.

We can ignore most of it if everything goes as planned (ie cycle the tank, follow the rules, do water changes etc).....it is when something goes wrong and questions are asked that we get into the mumbo jumbo stuff. We could, of course, just blame on a 'something in black box happens' though

ian

Agreed, and I think your example of hammering in a nail with a melon and getting a mess also goes for aquiring knowledge(for me anyway), to much information at once and its the old brain that becomes a mess

I have certainly learnt something today(cheesy as it sounds) even if I will not remember everything some bits will still linger on to be used in the future. I suppose being interested in keeping fish eventually leads to searching for information outside of the direct field, but for me it will be one small step at a time.

Melander

Melander wrote:

Omg thank you all for the replies!

@Christy, on my way with the water changes, just don't want to make it a habit me changing the water in the neighbours tank everyday.

You only need to change water every day until levels are back to normal (around) <20. Then you can go back to your normal routine, (once a week or so but thats another debate!)

Hi,

Sorry for not updating this thread, I just have not had internet access, and to be honest there has not been any huge updates.

My neighbour has not really been able to commit to the amount of water changes needed and it has been the same for myself which have meant that the conditions have changed very slowly.

Under the circumstances however it has gone well. The pH is down to 7.5 but the Nitrate is still too high at c. 40 but going down. At least it is going down and she will get there eventually.

I'm to give her some fish but have told her that she wont get any until the Nitrate is down more and have been stable for awhile so hopefully that will work as a carrot.

Cheers again for the help in this!

Melander