Somethings Not Right

[Akasha72]

Hi all. I need another pair of eyes and some thoughts please.
 
Somethings not right in my tank but I can't pin point anything necessarily as wrong.
 
All my cories are spinning in the sand, it's like they are really irritated by something but I can't see anything wrong with them. No obvious signs of parasites and I've not added anything new that hasn't been quarantined. This has been something new over the last week - 10 days.
 
I've done a full water test and all that looks off is my pH - it's dropped to 4.5 but that shouldn't be affecting my all SA fish surely? The reason for the drop will be because I removed the crushed coral from filter to make more room for my phosphate remover but I'm about to open my filter and put it back, even if that means sacrificing some of my ceramic media.
 
Ammonia is zero, as is nitrite. Nitrate is between 20 and 40. Phosphate is higher than I'd like at about 1.6 so as I'm opening a filter to replace the coral I'll change out my po4 remover at the same time.
 
I also had a dead harlequin this morning with no signs of illness before hand. It's all a bit odd. 
 
Could this dramaticly low pH be to blame? My tap pH is about 7.4 so a water change could help it back up along with the coral and that's my aim for the rest of today
 
Thoughts please

 

[Far_King]

This may be beneficial to read http/www.fishchannel.com/fish-health/the-role-of-ph-and-the-nitrogen-cycle.aspx
 
The coral may have been acting as a buffer which is no longer present and could have altered the water parameters.
 
Do you have a gh or kh test kit?

 

[Akasha72]

yes, I know my gH and kH are virtually zero straight from the tap which was why I had the coral in my filter. I was warned of a pH crash a couple of years ago and it looks like I've just rescued it from crashing. I've re-added the coral and done a 60 litre water change (tank volume 240 litres) and re-tested the pH and it's back up to around 6. (that's normal for my tank) I tested the tap water too, to be sure that they pH there hadn't lowered, but it's still around 7 - 7.5 which is it's normal level. I also add redbush tea to stain my water and so I tested my bucket pH to check that the tea wasn't dropping the pH and that was the same as the tap.
 
I'm in a process of ruling things out first.
 
I just don't want my cories to be sick and I've no idea why they are flicking and spinning in the sand. The dead harlequin could be nothing - just one of those things. My SAE's are also flicking but they have always flicked when stressed and they seem stressed right now but then soft water isn't their natural enviroment. I guess I'm trying to figure out if the pH is to blame or if it's something else.
I always figure things out better this way

 

[Far_King]

It may have been as simple as the pH going out of balance.  Fish can react quite strongly to that, more-so than other variables.
 
As that was what you changed and you saw a noticeable change in their behaviour I'd personally look at going back to how it was and keeping a close eye to see if things calm down; which you have now done so hopefully things will now be ok.

 

[Akasha72]

you're probably right - I hope your right! I'll admit to being both shocked and horrified when my pH test came out as it did. I've never seen it that low and I honestly didn't think the coral was doing anything - looks like I got that wrong!

 

[Far_King]

I'd have thought it would buffer the water in some way as it's releasing minerals but I'd certainly not have known to what degree it would raise pH.
 
That's why I linked that article as it confirmed it

 

[Akasha72]

sorry, not had chance to read the link yet. I've got five minutes now so I'll go read it

 

[Akasha72]

I think all I can do now is keep a watch on my cories and see if they stop flicking and spinning in the sand and re-test me pH first thing tomorrow. I can always do another water change tomorrow to help raise it some more if needed. 

 

[eaglesaquarium]

A drop of 1.5 on the pH scale like that is a fairly significant swing.  Depending on how fast it dropped, that could be the culprit.  The pH scale is logarithmic, which means that a 1.5 change in value is actually a change of 10^1.5 - or difference in the ratio of H+ to OH- ions of a factor of 31.6!   That's not a trivial change by any means.
 
 
And while a 4.5 pH wouldn't necessarily be a 'problem' for those fish in the wild, because that would be where they were born, grew and have lived... that would be their normal range.  Your fish were likely born, grew and have lived in an environment that's bounced in the range of 6.0-7.0... which means a dramatic difference from their 'normal'.  It could also be a difference in the hardness as well, as taking out the crushed coral allowing the pH to crash can only happen when the kH in the water is 'used up'.  So, the fish were dealing with not only a lower than normal (for them) pH, but also a lower than normal kH (for them) and likely even a lower than normal TDS (for them).  
 
Now that the pH has been restabilized with the addition of more crushed coral, its likely that the symptoms you noticed will subside as the fish get back to their regular routine.  But, keep an eye on things for more symptoms. 

 

[Akasha72]

I'm hoping that the symptoms I saw in my cories was because of the pH crash and nothing more. If things return to normal (I will be testing my pH daily for at least a week to make sure) and the symptoms disappear then I know what warning signs to watch for in the future and to add some more coral. 
 
So far all my fish seem really chilled out, they've been fed and they're now chilling on the sand or in the plants. I'm gonna wait til later and then just do a quick pH check to make sure it's not dropping again

 

[Akasha72]

cories have stopped flicking and started zooming around and playing again. Happy cories again - phew

 

[eaglesaquarium]

Glad to hear it.

 

[Akasha72]

pH has dropped again. It's between 4,5 and 5 ... it's crashing again by the looks of it. Once breakfast is over the buckets are coming out again 

 what have I done 

 

[Far_King]

Perhaps remove the peat as well for the moment - did you add more in when you removed the coral?

 

[Akasha72]

there's no peat in there Far_king what there was that I'd forgotten about was a media bag with some alder cones in. They were in my other filter. If you remember I run two JBL's on this tank. Yesterday I opened filter 2 and added back the coral and a fresh bag of po4 remover. When I checked my po4 this morning along with my pH I found it hadn't moved so I opened filter number 1 and that's when I found the alder cones. I'd completely forgotten about them and my guess would be that they are the culprit for the pH drop. 
I've removed the alder cones, added more coral and another bag of po4 remover, done another water change (just 30 litres this time) and now my pH is back up to about 6.5 - that's it's normal level. 
I'll still be keeping an eye on things for a week and if things remain stable I'll make a post about alder cones lowering pH as it might be useful info for other to have. I want to make certain that the cones were the culprit first though