Ph While Cycling?

[Shifty1303]

hey all! quick question regarding my new tank
 
have had a new 200l set up for a few days with some plants and thoroughly washed play sand in it and have added the first dose of ammonia today to begin cycling. when i tested the water i got the 3ppm of ammonia as expected but what i didnt expect was i got a reading of 8.2 for pH?!?! checked my old established tank and the pH in there is <7.4. any ideas???
 
thanks
 
edit: my tap water is pH~7.3 fresh. leaving a sample to stand for 24 hours to see if it changes there too

 

[Byron]

The test of the tap water standing will be useful; you can also vigorously shake some fresh tap water in a covered jar for a few minutes, then test.  Either method out-gases the CO2, which will then give you a more accurate pH reading, which may be higher depending upon the CO2.
 
That said, I do believe I have read other members mentioning pH shifts connected to ammonia cycling, but I'll leave it for one of them to elaborate or correct me.  I've never used ammonia to cycle, relying on fast growing plants and perhaps seeding bacteria.
 
Byron.

 

[Shifty1303]

ok so i just tested a tube of tap water with a single drop of the household 9.5% ammonia hydroxide im using and the ph went off the chart >8.8. seems this is the problem then. as long as i do a c.90% wc at the end of cycling this shouldnt be a problem right?

 

[ShinySideUp]

I'm not an expert but I have cycled a few tanks using ammonia and perhaps I got it right or perhaps not, but I didn't even check for pH. There were no fish in the water so I didn't really care much about anything else other than the triumvirate of ammonia, nitrite and nitrate. Once the filter was functioning I moved on to checking other parameters and of course doing a massive water change.

 

[Shifty1303]

ok thanks. i just thought id check to make sure the ph was acceptable for cycling. have no worries now about getting it back to tap water levels with a massive wc but is there a risk to the plants and/or biological activity in the filter if i drop the pH from over 8 to nearer 7 in such a short time? i know that would certainly spell doom for fish but unsure about the to be newly cycled filter??
 
thanks

 

[Byron]

ok thanks. i just thought id check to make sure the ph was acceptable for cycling. have no worries now about getting it back to tap water levels with a massive wc but is there a risk to the plants and/or biological activity in the filter if i drop the pH from over 8 to nearer 7 in such a short time? i know that would certainly spell doom for fish but unsure about the to be newly cycled filter??
 
thanks

Lowering the pH to around neutral will not kill the bacteria but merely slow it down.

 

[ShinySideUp]

ok thanks. i just thought id check to make sure the ph was acceptable for cycling. have no worries now about getting it back to tap water levels with a massive wc but is there a risk to the plants and/or biological activity in the filter if i drop the pH from over 8 to nearer 7 in such a short time? i know that would certainly spell doom for fish but unsure about the to be newly cycled filter??
 
thanks

Bacteria will be OK and most common aquatic plants couldn't give a monkeys. My present tank has a pH of about 7.6, my previous tank's was 6.5 (substrate differences) and my plants, my bacteria and most importantly, my Clown Loaches have not suffered at all.. The Clown's have acclimatised and although I (and specifically the Clowns) would prefer more acidic water, it hasn't done any harm.