ph during cycle

[sith j]

is it normal for the ph to swing back and forth during the fishless cycle.

75gal
at this point i have

1ppm of ammonia (using ace hardware 10% solution to dose)
4-5ppm of nitrites
between 20-50 nitrates its hard to tell on an ap test kit

when my nitrates started to climb and nitrites started to decrease my ph went from 7.0 to 6.0

my tap water is 7.5

also on my 10 gal that has been cycled for 6weeks the ph on that tank went from 6.8 to 7.5 in a couple of days and lost a couple of platys.

havent done any water changes during this week and havent changed any of the decor. not sure why everything is swinging so much. the one peram that i dont test for is hardness, also neither of the tanks are planted. the 10 has small pebble substrate and the 75 has sand if this makes a diff

i hope i gave enough info for an educated guess

thanks in advance

sith j

 

[Big Ben]

I find that high ammonia levels will rise pH as I'm doing a fishless cycle right now as well.

Tee decrease from 7.0 to 6.0 with the high nitrates, was probably because your waters buffering can't handle the high nitrates.

When your pH rose I think the problem is that your tap water has a pH of 7.5, so before adding it to your lower pH water, you need to get it down, otherwise it's just going to raise your lower pH.

Also if you add driftwood to your tank it will naturally lower the pH. What kind of filter do you have? If you have room for filter media you can add peat moss to lower pH as well.

 

[Elle2]

How long did you let your tap water sit before testing it? I was advised to let it sit for at least 24 hours. Mine starts out high (pH7) but if I let it sit and let the CO2 gas out for 24 hours it goes way down (6.2). I did a bit of research and found that my city water has a really low pH so letting sit seems to give me the accurate reading.

I wonder why your ten G was at 6.8 if your tap water is 7.5? I wonder if the tap water really is that high? Do you have any coral or light rocks in the 10 G?

I just finished my fishless cycle and my pH did drop drastically at one point but I think it was mostly the result of my tap water actually being quite low.

 

[sith j]

i didnt think about letting my tap water set, i assumed that it was what is was. i thought that the cycle dropped it from 7.5 to 6.5. in my ten gal i do have some rock as decor. i think there is a picture of it in my gallery. the rock is limestone i think. i will let some water set out and then test. the rock could be raising the ph.

i checked you cant see my rock in my gallery, will get a pic

 

[Lonewolfblue]

Yes, limestone raises ph. It's good for cichlid tanks that need a higher ph, but not really recommended for most other fish, as it will raise your ph to over 8 i believe. The rocks that don't raise ph are rocks like slate, granite, quartz, etc.

 

[Elle2]

Even if your cycle lowered your pH I am surprised that it would lower it that drastically... especially if you have limestone in there (although this would depend on how long it was in there I suppose). Blue wolf and others will know much more about this than me, but from 7.5 to 6 seems pretty drastic... I think you may find that your tap water is lower than 7.5 afterall...

I was told that having a low pH will stall your cycle though so you will want to get it back up a bit pretty soon. Although mine was down around 6.4 for a few days and my cycle still only took 3 weeks to the day.

 

[sith j]

i tested my tap water after it set out for 24 hours. it in fact was at 6.8 not the 7.5 that i was getting from immediate testing. well i do have good news, my 75 gal tank just tested 0 ammonia 0nitrite and 10 nitrate, i just did a large water change and will put one or two fish from my 10 gal to feed the bacteria will i make up my stinking mind on what i want to put in the tank, i must have changed my mind a 1000 times already. i am very exited. although should i take the rocks out of my tanks and find something else. they look really nice though. i'll keep testing my ph, if it stays at 6.8-7.0 i dont think i'll worry i just dont want it to swing so drastically.

 

[Lonewolfblue]

Just a little insite on Cycling. Cycling is an acidic process. When your tank is nearing the end of your cycle, you will more than likely see a drop in ph. If you have a fairly high kh, you probably won't see much of a drop, but a lower kh means a weaker buffer, which means ph drops. This is completely normal. You can also use limestone or crushed coral to raise your kh during the cycle, and when done, remove them. But remember it doesn't work immediately. It took 2 weeks before I really started to see any change in my kh with using crushed coral in my filter.

When I did my fishless cycle on my 55G, as many in here know in my thread I did while cycling, near the end, my tank ph dropped from 7.2 to 6.0. Was probably lower, as 6.0 is the low end of the test kit. So I did PWC's during the end of my fishless cycle to try to keep my ph as high as possible. And my tank was completely cycled within a week of that ph drop. Hope this gives you a little clearer idea as to what is actually going on.

 

[Elle2]

Well I guess that explains what happened to mine then. Someone told me it could stall the cycle- but luckily it didn't seem to. If your pH is naturally low would keeping a coral or limestone rock as a decoration be a suitable alternative to adding crushed coral to the filter? For the moment I have been adding baking soda but I have to monitor it very closely- it will stay very stable for about 4-5 days but then it drops suddenly.

congrats on the completed cycle sith j

 

[Lonewolfblue]

You can add a limestone decor, yes. But you still may need to add some baking soda, as it will take a little bit before the limestone starts disolving, thus raising the kh. It's not instant.

 

[TomK2]

Water with a pH of 7 or below is generally rather low in KH, hence the nuetral to acidic pH due to the absence of carbonate to buffer the pH higher. From what I have read, nitrifying bacteria are significantly impaired by a pH of less than 6.5, and nitrification stops at a pH of 6.0 (note that this won't kill the bacteria right away, but conversion of ammonia to nitrate will stop). So, pH below 6.5 would be expected to take longer to cycle. Yes, nitrification is a slightly acidifying process. It is harder to have a stable pH with low KH water.

 

[sith j]

my ph on both tanks is back to 6.0 both tanks have a some limestone as decorations, i have two pieces that are bigger than my hand in my 10gal and my ph is still low. my newly cycled 75 has some small pieces but not much and is also at 6.0. do i need to add baking soda and if i do, how much per gal, all the fish seem fine and no ammonia or nitrite, if i do a pwc the ph goes up a little but after 24 hours it fall right back.\


what do you guys and gals think

 

[tropicfishman]

I have heard its best to let it set out for 24 hours, but oddly mine didn't show any difference after 24 hours, I think its because I used a container with a lid lol

 

[sith j]

how much baking soda do you add per gal to slowly increase to say 7.0 over a week period i guess

sj

 

[Lonewolfblue]

http://dataguru.org/misc/aquarium/calKH.asp