Severe Ph Problems

[rixy]

my brother in law has a jewel rio 400 with the internal filter and a fluval 404.he has a fine gravel substate,4 real plants and 4 artificial plants.fish include tiger barbs,rainbows,2 silver sharks.i would class the tank as understocked.their are no rocks or bogwood in the tank.ph of water from tap is 7.5 ish and ph of tank water is 5.5 ish.howit has been like this for a couple of months(i found out 3 days ago)what can we dowater is changed once a week(40-50%)and the tank is immaculate.please help as approx 20 fish(mostly tiger barbs) have died in the last month.

 

[rdd1952]

I've never heard of the pH dropping that much once in the tank without something like bogwood, peat or CO2 (does he use CO2 for the plants) causing it. Has he checked the KH of the tap water? That is a measure of the buffering capacity of the water. The higher the KH, the more stable the pH will be regardless of other agents that normally effect it. The fish he has would probably be fine with a pH of 5.5 but it isn't their optimal pH.

I think part of the problem is the large water changes. I would cut the water change amount down to about 15% (the fish he has aren't big waste producers so the water shouldn't be that bad after a week) as the large water are causing too much swing in the pH. If the tap pH is 7.5 and the tank is 5.5 and you do a 50% water change, you raise the tank pH to about 6.5. That is a huge change for the fish and is probably the problem. Fish can adjust to a stable pH but struggle with one that is in constant swing.

 

[reg2k2]

Definitely check both tap and tank for KH level.
My tap measures 0KH, and my tank used to drop so low, too (lowest measure on my test being 6.0).

 

[rixy]

so if we check the kh,what do we do thendo we need to add calcium gravel to the external to raise the ph?

 

[reg2k2]

Yes, that's what I do. A minimum of 4-5deg KH is recommeneded for stable pH, although my tank comes up to 3deg (0 from tap)...and things seem fine.

Baking soda is another option, any additional water needing to be treated as well.

 

[fishing4exotics]

Sound like pH crash. Caused by too much decaying matter in your tank. detritus and dead plant matter in your substrate and filter. Try cleaning out your filter and gravel vac without harming your plants. Then add some crushed coral in your gravel and if possible in your filter. This is keep your pH more stable than adding a buffer like baking soda.

 

[rdd1952]

Be careful with the crushed coral. It does work and I have used it before but a couple teaspoonfuls in the filter will probably be enough to keep your tank pH steady. It really doesn't take much so don't grab a handful and throw it in there.

 

[rixy]

thanks everyone.plants only been in tank about 4 days so there is no decaying matter in the tank,or,filter.new substrate(aquarium gravel) was put in the tank approx 10 days ago.we have tryed everything,but to no avail.we bought some crushed coral this morning,so,we'll see how that goes.

 

[fishing4exotics]

Hope it works out for you rixy