skimmer?

[baldomero]

i went on vacation left my tank attended by a novice she did a good job with the feeding etc...... only thing my skimmer was on but the water level in the skimmer was real low.i put it back to the regular level and it was foaming like crazy. my question is if the skimmer wasnt dumping foam in the collection cup could that have made my nitrates go up. what i mean is the level was so low it didnt even reach the neck of the skimmer.