Alkalinity is going, going, GONE!

[btrecordingz]

Hey guys, my 90 gallon tank in my basement is throwing me a massive curveball. Within the last two weeks the alkalinity will just not hold. When I first realized it is when the tinfoil barbs started flashing off the rocks and the wood. This tank has been set up for YEARS and never had this problem.

Little backround on the tank. 90 gallon with 3 full grown silver dollars and 2 full grown tinfoil barbs. Magnum 350 deluxe for the filter. Undergravel with a marineland powerhead. Substrate is regular aquarium gravel and large rocks with misc pieces of driftwood.

I know the wood will lower the PH over time but this has been the setup for probably about 10 years now. Why would this happen out of the blue? Water is changed weekly, between 15%-25%. Filter media changed every 3rd week. Bio-wheels rinsed in used water at the end of every other month or whenever they start to slow down. Any ideas?

 

[jcardona1]

when you say alkanility you mean in terms of buffering capacity / kh / carbonate hardness right? this happens on mature tanks. try using crushed coral to raise your water's hardness a bit in order to maintain a better buffering capacity

 

['vspec']

Interesting considering you say nothing has changed in years.

Ca & Mg relationship is prob better served if your breaking it down, however id be looking at starting up the process of ilimination first.

based on what youve already mentioned id look at the below.

Ask your water board for the latest test results. @25% tap water weekly, id question its inability to buff alk if you haven't experienced issues till now. assuming your using tap water yeah?

Id investigate & rule out your potential atmo Co2 levels in the basement. gas heaters running, bad air circulation, to many parties goers ect ect

id def be having a closer look at your tannic & humic organic contributers.

You have plants in the system?

You running carbon at all?

 

[nockturnal]

i'm having this same issue. Total alkalinity KH ppm is just about 0
everything else is in the range that it needs to be in. and all of the LFS give me a different answer the only thing they have in common is "buy this" and ideas ?

 

[Andrewtfw]

Compare the Kh of your tap/well water to that of the tank shortly after a water change. Public water varies in Ph/Kh throughout the year and from year to year. You said nothing changed, but fish grow over time and the bioload is impacted as a result. Changes in frequency/quantity of feeding also will impact.

 

['vspec']

As mentioned, It means you have an acidic contribution depleting your alk.

You need to bring it up to min 50-100p via what ever means you choose to deploy, if your buying at the LFS, then buy correctly - add seachem alk buffer.

although, once again, we're fishing in the dark & by being extremely general. I have zero clue as to your given system and the to & fro's that contribute to it. Im still trying to master making pumkin pie out of pig sh^t, but she's not easy!