Ph Dropping

[Mickfender]

Hi just looking for a bit of advice on my fishless cycle. Im on day 25 at moment and my ph has been dropping slowley since day 17,it was 8.5 then day 19 was 7.5,until day 24 dropped to 7.0.Just wondered if this is normal or should i do a water change. I havent changed water at all during fishless cycle,my ammonia has been dropping from about 4/5 ppm to zero in 24 hrs for about a week now. I think im in nitrite spike as this is off the chart every day. I have a Fluval Roma 125 tank,and a Tetratec ex700 filter. Thanks Mick.

 

[backtotropical]

Hi Mick,

It is normal for the pH to drop during the cycle, so nothing to worry about. Nitrate is acidic, so as the bacteria convert your nitrite to nitrate, the pH drops.

The problem with it is that if your pH drops much lower, the bacteria will slow down their reproduction, and eventually stop reproducing when pH gets down to around 6.

Obviously you don't want this to happen, but there is a simple solution, water change.

The optimum pH for bacteria growth is around 8 - 8.5, so do a water change to get rid of some nitrate and bring your pH back up again. Start with say 50% and see how it goes.

Make sure to use dechlorinator for the fresh water as your bacteria colony will be fairly fragile at the moment and you don't want any die off due to the chlorine in your tap water.

Its probably best to keep a cursory eye on your pH until your cycle is finished, as the pH may well start to fall again as the bacteria process more and more nitrite into nitrate.

Hope that makes sense.

Cheers

BTT

 

[Twinklecaz]

It's 125 litres?

I had the same prob. Do a big water change and see if that works. If not add about 2.5 (assuming it is 125 litres) tablespoons of Bicarbonate of Soda.

 

[OldMan47]

I am going to go out on a limb here and suggest that you drop the nitrite levels down to something you can read with your test kit by doing a massive water change. It will reset your pH value and may even promote a bit faster cycling than you have been experiencing.

 

[Mickfender]

Thanks for the advice i will do a water change and see how it goes from there.Thanks Mick

 

[Mickfender]

Hi all update on ph dropping. Day 26 testing, PH-6.5. Ammonia-0. Nitrite-off the scale.Done a 50% water change tested after 30 mins. PH-7.0. Ammonia-0. Nitrite-off the scale. Nitrate-off the scale. Added 5ml ammonia then tested again after 25 mins. PH-7.5. Ammonia-about 3 or 4 ppm. Nitrite-off the scale. Nitrate-off the scale.Any comments on results welcome,thanks Mick

 

[waterdrop]

I'm going to agree with BTT that pH dropping is a common occurance in fishless cycling and a good water change is an excellent first approach to the problem. I'm also going to agree with OM47 that a really strong water change that clears out most of the nitrite and nitrate is going to do two things, bring the pH up the most and also clear out the excess nitrite and nitrate so that the bacteria can grow better.

The results of your 50% water change show that not enough happened. I'd do a "down to the gravel" water change (with dechlor and recharge of ammonia of course) so that you get a better "reset" and let us know if you can achieve a higher pH from that.

~~waterdrop~~

 

[Mickfender]

Hi WD thanks for the advice.Its day 29 now and i changed water down to the sand just about,it was 100 ltrs out of about 120 in tank.Added ammonia to bring up to between 3-4 ppm,tested after 45 mins.PH-8.5, Ammonia-3-4 ppm, Nitrite still off the scale,Nitrate still off the scale. Was hoping the nitrite would go done a bit but still to high for my test kit and the same for nitrate. Thanks Mick

 

[JoshuaA]

Hi WD thanks for the advice.Its day 29 now and i changed water down to the sand just about,it was 100 ltrs out of about 120 in tank.Added ammonia to bring up to between 3-4 ppm,tested after 45 mins.PH-8.5, Ammonia-3-4 ppm, Nitrite still off the scale,Nitrate still off the scale. Was hoping the nitrite would go done a bit but still to high for my test kit and the same for nitrate. Thanks Mick

Same happened to me, I did a down to gravel filled it all back up. Re dosed ammonia and tested for Nitrite/Nitrate and pH. Nitrite was 0.5 an hour after the near complete utter removal of water and under 12 hours it was so far off the scale and the pH had gone from 8.4 to 7.4 super fast. I think a lot of water changes are going to need to be done to prevent the pH crashing massively again.

 

[Mickfender]

Thanks joshuaA,just done done to gravel change and added ammonia, gonna wait 45 mins then test hope its gone down some.

 

[backtotropical]

Any results for us, Mick?

 

[Mickfender]

Hi backtotropical,here are my latest results. After very large water change and top up of ammonia. PH-8.5, Ammonia-3+, Nitrite-at the top of my scale which is 3.3 poss a bit more, Nitrate-110 is my test limit,it was very slightly under this. Just tested again 23 hrs later, PH-7.5, Ammonia 0.6, Nitrite-off the scale, Nitrate-off the scale. So ph still dropping daily,and nitrite/nitrate way off the scale.

 

[N0body Of The Goat]

It might be worth taking a good sized sample (~20ml) to a LFS and get them to test it for you (they may charge ~£1 for this, but I've had 3 tests done for free while buying other bits and bobs).

My Nutrafin nitrate and nitrite tests were awful to read off the results table on the manuals! When I was getting bright purple nitrate that looked nothing like the chart and I guessed it was the maximum of 110mg/l, plus the nitrite rsults were colourless and my chart's lightest reading was pale purple, I actually had 0 nitrite and 15mg/l!

Its a good idea to do the above every few months anyway, as a way of calibrating your home kit.

 

[OldMan47]

That is a big pH drop Mick. If you cannot control pH with simple water changes, the next step during a fishless cycle is to add in some sodium bicarbonate, baking soda. Do make note of the fact that you had trouble controlling pH with water changes because it likely means that you have tap water with a very low KH. Low KH water is something that we may need to deal with after your cycle is complete.

 

[Mickfender]

Thanks for the replys,now into day 33 and my ph has held at 7.5 for 3 days now, but now my ammonia processing is slowing down,for a cpl weeks has been doing 3-4 ppm in 24 hrs,but day 31, ammonia 0.6 after 24 hrs, added ammonia, Day 32 0.6 ammonia after 24 hrs,added ammonia to 3-4 ppm, and now today ammonia 2.4 after 24 hrs. Is this normal or is something going wrong.