75% Water Change Too Much While Fish In Tank?

[jamesmacc]

hey everyone, added 8 fish about 9 days ago now and my nitrates are abit higher than i would have liked, i put this down to the ammonia i had been adding up until the night before the fish arrived, i had done a water change down to the substrate 3 days before they arrived but thought that the 2 days of adding ammonia might have raised them. did a 50% water change and they dont like they have gone down much on the api test. im running a tetra 1200 and an eheim 2217 externals filters.
the other thing is the lot number on my liquid test kit is 17A1109. so could expire november 2009 or september 2011. would this make a difference. i dont realy want to have to order another kit but i will if i need too.
let me know what you think, the nitrate is about 80 ppm

 

[ZoddyZod]

75% change is not a concern, as long as the water is reasonably temperature matched, it wont do any harm.

80ppm nitrate is nothing to get too worried about either. Any idea what the nitrate readings are from your tap? Might even be the same.

 

[jamesmacc]

75% change is not a concern, as long as the water is reasonably temperature matched, it wont do any harm.

80ppm nitrate is nothing to get too worried about either. Any idea what the nitrate readings are from your tap? Might even be the same.

my tap water is almost zero last time i checked it but i will check it again later, whats the maximum level nitrate should get too, i have just added 2 live plants. hopefully they will soak up a little bit of it. im just worried because this is my first tank and i want to keep the fish in the best conditions i can.
cheers,
james

 

[ZoddyZod]

although high levels of nitrate can be tolerated by fish (I've seen quotes of 400ppm being ok), it is still best to keep them as low as possible.

If your tap water has no nitrate, and your tank isn't heavily stocked and not over-fed, I wouldn't expect to see anything over 40ppm build up in there between weekly water changes, probably much lower.

depending on the plants, they may or may not help (dependant on speed of growth) but as stated, you shouldn't suffer from high nitrates anyway.

 

[the_lock_man]

my tap water is almost zero last time i checked it but i will check it again later, whats the maximum level nitrate should get too, i have just added 2 live plants. hopefully they will soak up a little bit of it. im just worried because this is my first tank and i want to keep the fish in the best conditions i can.
cheers,
james

There isn't a set maximum, really, some fish are less tolerant of nitrate than others. However, unless you have particularly intolerant fish, a regular weekly water change schedule prevents nitrate reaching dangerous levels.

80ppm nitrate .... Any idea what the nitrate readings are from your tap? Might even be the same.

Hope not - legal max is 50ppm in the UK.

 

[minnnt]

You can do however much of a water change you want, as long as you leave enough space for your fish to stay upright. A decent temperature match and adequate dechlor used and you will be fine.

If you are worried about high nitrates then maybe consider live plants/more live plants.

 

[ZoddyZod]

80ppm nitrate .... Any idea what the nitrate readings are from your tap? Might even be the same.

Hope not - legal max is 50ppm in the UK.

*adds note to non-existent aquarium notebook*

 

[snazy]

80ppm nitrate is nothing to get too worried about either. Any idea what the nitrate readings are from your tap? Might even be the same.

It is illegal to have 80ppm nitrate in drinking water. Although not toxic to fish, nitrate is toxic to humans and the allowed maximum is 10ppm.

 

[jamesmacc]

i restested it again and it looks like 40 ppm, maybe i was doing it in the wrong light or maybe the plants have started to absorb some, i noticed they have started sprouting roots quite fast.
thanks for all your tips and advise

 

[Aqua Tom]

80ppm nitrate is nothing to get too worried about either. Any idea what the nitrate readings are from your tap? Might even be the same.

It is illegal to have 80ppm nitrate in drinking water. Although not toxic to fish, nitrate is toxic to humans and the allowed maximum is 10ppm.

Here is a quote from the drinking water inspectorates website,

"Why is it necessary to control nitrate in water?
Very high amounts of nitrate in drinking water can cause methaemoglobinaemia (blue baby syndrome) in very young children. This is a potentially fatal illness where nitrate is converted to nitrite in the gut and interferes with the absorption of oxygen by the blood. This extremely unusual illness only occurs when nitrate intake is very high. The last recorded case in the UK occurred in the 1950s and was associated with the use of a shallow private well. However cases still continue in other parts of the world where there is little or no management of water supplies. The first legal standard for nitrate was set in 1980 and the current drinking water standard is 50 mg/l. This EU standard is based on the World Health Organisation's guideline value for drinking water, which is also 50 mg/l. This level is intended as a safeguard against methaemoglobinaemia."


Tom

 

[BigbruiserAl]

80ppm nitrate .... Any idea what the nitrate readings are from your tap? Might even be the same.

Hope not - legal max is 50ppm in the UK.

*adds note to non-existent aquarium notebook*

ops tom already answered

 

[fishguy2727]

Nitrate itself isn't the problem. The problem is that there are many bad things that build up in water requiring water changes. We don't have test kits for things like growth inhibiting hormones and dissolved organic compounds. The good thing is that in most tanks they correlate very well with nitrate. If nitrate is low, that usually means that the other bad things are too. The limitation to that is that in a planted tank the plants will remove nitrate but not these other things. This is why even in a planted tank with little or no nitrate it still important to do weekly water changes, even if they are not as large.

Although a 75% water change is not a problem on its own, someone jumping in to one who has never done water changes that large before is. The large the water change is the more drastic the change is. For example, a slight temp different may do nothing in a 25% water change but stress all the fish in a 75% water change. Because of this I suggest you step up slowly to larger water changes.

Another thing to consider is that over time the chemistry of your tank changes. If you do weekly water changes this will help keep your tank's water closer to that of your tap, meaning larger water changes are less likely to cause any issues. If you wait to do them every month or even longer the difference between your tank's water and the tap is larger and more likely to cause problems for the fish.

As stated no tap water should be putting out 80ppm nitrate. It is common though to have tap water with 5-15ppm or more. This is why it is important to check your tap's nitrate to see how much it is changing throughout the week.

My general recommendation for water changes is weekly and at least 25%, larger if needed to keep nitrate under 20ppm before a water change.

 

[raptorrex]

*adds note to non-existent aquarium notebook*

+1 here. LOL

75% is no problem, even to a novice.
though if you have big fish, they may get stressed by the lack of space.

 

[minnnt]

+1 on RR